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ISPRS Int. J. Geo-Inf., Volume 12, Issue 2 (February 2023) – 57 articles

Cover Story (view full-size image): The performance of a machine learning algorithm depends on the underlying data representation. Geospatial data come in many different shapes and forms, including points of interest, boundaries, trajectories, images and many more. To maximise the performance of the machine learning algorithms operating on such data, they should be converted into a representation that encodes the semantics by mapping similar entities to similar representations. Self-supervised representation learning (SSRL) performs this task automatically without the need for expensive data annotation. This article reviews the existing research literature on SSRL in the field of geographical information science and discusses different types of representations learnt, SSRL models used, downstream applications, and performance improvements. View this paper
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20 pages, 10658 KiB  
Article
Energy-Efficient 3D Path Planning for Complex Field Scenes Using the Digital Model with Landcover and Terrain
by Baodong Ma, Quan Liu, Ziwei Jiang, Defu Che, Kehan Qiu and Xiangxiang Shang
ISPRS Int. J. Geo-Inf. 2023, 12(2), 82; https://doi.org/10.3390/ijgi12020082 - 20 Feb 2023
Cited by 6 | Viewed by 2286
Abstract
Path planning is widely used in many domains, and it is crucial for the advancement of map navigation, autonomous driving, and robot path planning. However, existing path planning methods have certain limitations for complex field scenes with undulating terrain and diverse landcover types. [...] Read more.
Path planning is widely used in many domains, and it is crucial for the advancement of map navigation, autonomous driving, and robot path planning. However, existing path planning methods have certain limitations for complex field scenes with undulating terrain and diverse landcover types. This paper presents an energy-efficient 3D path planning algorithm based on an improved A* algorithm and the particle swarm algorithm in complex field scenes. The evaluation function of the A* algorithm was improved to be suitable for complex field scenes. The slope parameter and friction coefficient were respectively used in the evaluation function to represent different terrain features and landcover types. The selection of expanding nodes in the algorithm depends not only on the minimum distance but also on the minimum consumption cost. Furthermore, the turning radius factor and slope threshold factor of vehicles were added to the definition of impassable points in the improved A* algorithm, so that the accessibility of path planning could be guaranteed by excluding some bends and steep slopes. To meet the requirements for multi-target path planning, the improved A* algorithm was used as the fitness function of the particle swarm algorithm to solve the traveling salesman problem. The experimental results showed that the proposed algorithm is capable of multi-target path planning in complex field scenes. Furthermore, the path planned by this algorithm is more passable and more energy efficient. In this experimental environment model, the average energy-saving efficiency of the path planned by the improved algorithm is 14.7% compared to the traditional A* algorithm. This would be beneficial to the development of ecotourism and geological exploration. Full article
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<p>Establishment of the experimental environment model: (<b>a</b>) grid coordinate mapping of model data; (<b>b</b>) multi-layer feature map.</p>
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<p>Landcover distribution of the experimental model.</p>
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<p>Terrain information of the experimental model.</p>
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<p>Technical route for 3D path planning in complex field scenes.</p>
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<p>Schematic of the three situations.</p>
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<p>A 45° angle of vehicle turning.</p>
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<p>A 90° angle of vehicle turning: (<b>a</b>) short radius; (<b>b</b>) long radius.</p>
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<p>A 135° angle of vehicle turning.</p>
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<p>The effect of the terrain factor in the improved A* algorithm: (<b>a</b>) experimental result of traditional A* arithmetic; (<b>b</b>) experimental result from the improved A* algorithm (including landcover) excluding the terrain factor; (<b>c</b>) experimental result from the improved A* algorithm (including landcover) including the terrain factor.</p>
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<p>The effect of the terrain factor in the improved A* algorithm: (<b>a</b>) experimental result of traditional A* arithmetic; (<b>b</b>) experimental result from the improved A* algorithm (including landcover) excluding the terrain factor; (<b>c</b>) experimental result from the improved A* algorithm (including landcover) including the terrain factor.</p>
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<p>The effect of the landcover factor in the improved A* algorithm: (<b>a</b>) experimental result of the traditional A* algorithm in the 3D model; (<b>b</b>) experimental result from the improved A* algorithm (including terrain) without the landcover factor; (<b>c</b>) experimental result from the improved A* algorithm (including terrain) including the landcover factor.</p>
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<p>Path length statistics.</p>
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<p>Multi-target path planning for (<b>a</b>) medium vehicles and (<b>b</b>) large vehicles.</p>
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<p>Multi-target path planning for (<b>a</b>) medium vehicles and (<b>b</b>) large vehicles.</p>
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<p>Slope statistics for two types of vehicles: (<b>a</b>) slope angle statistics in the driving direction for medium vehicles; (<b>b</b>) slope angle statistics in the driving direction for large vehicles.</p>
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<p>Turning angle statistics for the two types of vehicles.</p>
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24 pages, 9616 KiB  
Article
Mapping Cropland Extent in Pakistan Using Machine Learning Algorithms on Google Earth Engine Cloud Computing Framework
by Rana Muhammad Amir Latif, Jinliao He and Muhammad Umer
ISPRS Int. J. Geo-Inf. 2023, 12(2), 81; https://doi.org/10.3390/ijgi12020081 - 20 Feb 2023
Cited by 3 | Viewed by 3768
Abstract
An actual cropland extent product with a high spatial resolution with a precision of up to 60 m is believed to be particularly significant in tackling numerous water security concerns and world food challenges. To advance the development of niche, advanced cropland goods [...] Read more.
An actual cropland extent product with a high spatial resolution with a precision of up to 60 m is believed to be particularly significant in tackling numerous water security concerns and world food challenges. To advance the development of niche, advanced cropland goods such as crop variety techniques, crop intensities, crop water production, and crop irrigation, it is necessary to examine how cropland products typically span narrow or expansive farmlands. Some of the existing challenges are processing by constructing precision-high resolution cropland-wide items of training and testing data on diverse geographical locations and safe frontiers, computing capacity, and managing vast volumes of geographical data. This analysis includes eight separate Sentinel-2 multi-spectral instruments data from 2018 to 2019 (Short-wave Infrared Imagery (SWIR 2), SWIR 1, Cirrus, the near infrared, red, green, blue, and aerosols) have been used. Pixel-based classification algorithms have been employed, and their precision is measured and scrutinized in this study. The computations and analyses have been conducted on the cloud-based Google Earth Engine computing network. Training and testing data were obtained from the Google Earth Engine map console at a high spatial 10 m resolution for this analysis. The basis of research information for testing the computer algorithms consists of 855 training samples, culminating in a manufacturing field of 200 individual validation samples measuring product accuracy. The Pakistan cropland extent map produced in this study using four state-of-the-art machine learning (ML) approaches, Random Forest, SVM, Naïve Bayes & CART shows an overall validation accuracy of 82%, 89% manufacturer accuracy, and 77% customer accuracy. Among these four machine learning algorithms, the CART algorithm overperformed the other three, with an impressive classification accuracy of 93%. Pakistan’s average cropland areas were calculated to be 370,200 m2, and the cropland’s scale of goods indicated that sub-national croplands could be measured. The research offers a conceptual change in the development of cropland maps utilizing a remote sensing multi-date. Full article
(This article belongs to the Special Issue Geomatics in Forestry and Agriculture: New Advances and Perspectives)
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<p>The division of the agro-ecological study into specialized subfields (RAEZs). The distribution of comparative training data in machine learning algorithms is also shown in the illustration. Based on the pixel classification, the analyzed supervised areas match.</p>
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<p>10m to 60m Sentinel-2 MSI data were composed for six time-frames. Eight bands were formed for every time frame (e.g., time 1: Julian days 1–60), taking the median value of one pixel for each cycle (SWIR 1, SWIR 2, Red, NIR, Black, Cirrus, Aerosol, and B.</p>
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<p>Sub-meter to 10 m image details with a relatively good resolution for Pakistan. Illustration of Pakistan’s comparison training data obtained using high-resolution imagery sub-meter to 10 m.</p>
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<p>A review of cropland planning techniques. The research used classification algorithms for pixel-based supervised machine learning. The study was carried out on the cloud infrastructure framework of Google Earth Cloud.</p>
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<p>Land Classifications map of Pakistan.</p>
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23 pages, 13050 KiB  
Article
Land Use Change and Hotspot Identification in Harbin–Changchun Urban Agglomeration in China from 1990 to 2020
by Shouzhi Chang, Jian Zhao, Mingming Jia, Dehua Mao, Zongming Wang and Boyu Hou
ISPRS Int. J. Geo-Inf. 2023, 12(2), 80; https://doi.org/10.3390/ijgi12020080 - 20 Feb 2023
Cited by 3 | Viewed by 2330
Abstract
An urban agglomeration is a growth pole of regional development. However, the land uses have changed significantly due to the impacts of intense human activities. Analyzing the overall change characteristics of land use and hotspots has direct reference value for the formulation and [...] Read more.
An urban agglomeration is a growth pole of regional development. However, the land uses have changed significantly due to the impacts of intense human activities. Analyzing the overall change characteristics of land use and hotspots has direct reference value for the formulation and implementation of land use management measures. This study used a complex network of analysis methods and a cluster and outlier analysis to study the land use changes and hotspots in the Harbin–Changchun urban agglomeration (HCUA). The results showed that farmland exhibited a high weighted degree of centrality, indicating that it is the key land type in the HCUA land use change network. From 1990 to 2000, the land use change in each city mainly manifested as the loss of ecological land, whereas from 2000 to 2010 it manifested as the restoration of ecological land. From 1990 to 2020, the average path length of the network in 11 cities was less than 1.4, which was reduced in 10 cities, indicating that the stability weakened and land use change more likely occurred. Specifically, the area of ecological land reduction hotspots gradually decreased from 15,237.81 km2 to 11,533.95 km2. In the ecological land concentration area, the change hotspots for ecological land use and ecological function had strong consistency. The distribution and changes of hotspots were affected by policies and the terrain. The increase in ecological land around urban built-up areas, however, did not improve the landscape connectivity. Therefore, in the planning of ecological land use, attention should be paid to the landscape pattern. Full article
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<p>Location of the study area.</p>
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<p>Land use maps in different years: (<b>a</b>) 1990; (<b>b</b>) 2000; (<b>c</b>) 2010; (<b>d</b>) 2020.</p>
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<p>Overall workflow of the land use change and hotspot analysis of the urban agglomeration.</p>
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<p>Sampling points of the transect.</p>
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<p>Changes in PD along the transect under different window sizes.</p>
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<p>Proportions of land use types in each year.</p>
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<p>Changes in average path length in each city.</p>
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<p>Hotspots of ecological land change: (<b>a</b>) 1990 to 2000; (<b>b</b>) 2000 to 2010; (<b>c</b>) 2010 to 2020.</p>
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<p>Hotspots of ecological land change: (<b>a</b>) 1990 to 2000; (<b>b</b>) 2000 to 2010; (<b>c</b>) 2010 to 2020.</p>
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<p>Example of high–high clusters around built-up areas.</p>
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<p>Area changes in high–high clustering and low–low clustering in different periods.</p>
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<p>Complex network of land use changes in different periods in different cities.</p>
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<p>Complex network of land use changes in different periods in different cities.</p>
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<p>Complex network of land use changes in different periods in different cities.</p>
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<p>Hotspot identification results of landscape index changes: (<b>a</b>) changes in PD from 1990 to 2000; (<b>b</b>) changes in PD from 2000 to 2010; (<b>c</b>) changes in PD from 2010 to 2020; (<b>d</b>) changes in MPS from 1990 to 2000; (<b>e</b>) changes in MPS from 2000 to 2010; (<b>f</b>) changes in MPS from 2010 to 2020; (<b>g</b>) changes in COHESION values from 1990 to 2000; (<b>h</b>) changes in COHESION values from 2000 to 2010; (<b>i</b>) changes in COHESION values from 2010 to 2020; (<b>j</b>) changes in AI values from 1990 to 2000; (<b>k</b>) changes in AI values from 2000 to 2010; (<b>l</b>) changes in values AI from 2010 to 2020.</p>
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<p>Hotspot identification results of landscape index changes: (<b>a</b>) changes in PD from 1990 to 2000; (<b>b</b>) changes in PD from 2000 to 2010; (<b>c</b>) changes in PD from 2010 to 2020; (<b>d</b>) changes in MPS from 1990 to 2000; (<b>e</b>) changes in MPS from 2000 to 2010; (<b>f</b>) changes in MPS from 2010 to 2020; (<b>g</b>) changes in COHESION values from 1990 to 2000; (<b>h</b>) changes in COHESION values from 2000 to 2010; (<b>i</b>) changes in COHESION values from 2010 to 2020; (<b>j</b>) changes in AI values from 1990 to 2000; (<b>k</b>) changes in AI values from 2000 to 2010; (<b>l</b>) changes in values AI from 2010 to 2020.</p>
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15 pages, 1965 KiB  
Article
Spatio-Temporal Transformer Recommender: Next Location Recommendation with Attention Mechanism by Mining the Spatio-Temporal Relationship between Visited Locations
by Shuqiang Xu, Qunying Huang and Zhiqiang Zou
ISPRS Int. J. Geo-Inf. 2023, 12(2), 79; https://doi.org/10.3390/ijgi12020079 - 20 Feb 2023
Cited by 3 | Viewed by 2385
Abstract
Location-based social networks (LBSN) allow users to socialize with friends by sharing their daily life experiences online. In particular, a large amount of check-ins data generated by LBSNs capture the visit locations of users and open a new line of research of spatio-temporal [...] Read more.
Location-based social networks (LBSN) allow users to socialize with friends by sharing their daily life experiences online. In particular, a large amount of check-ins data generated by LBSNs capture the visit locations of users and open a new line of research of spatio-temporal big data, i.e., the next point-of-interest (POI) recommendation. At present, while some advanced methods have been proposed for POI recommendation, existing work only leverages the temporal information of two consecutive LBSN check-ins. Specifically, these methods only focus on adjacent visit sequences but ignore non-contiguous visits, while these visits can be important in understanding the spatio-temporal correlation within the trajectory. In order to fully mine this non-contiguous visit information, we propose a multi-layer Spatio-Temporal deep learning attention model for POI recommendation, Spatio-Temporal Transformer Recommender (STTF-Recommender). To incorporate the spatio-temporal patterns, we encode the information in the user’s trajectory as latent representations into their embeddings before feeding them. To mine the spatio-temporal relationship between any two visited locations, we utilize the Transformer aggregation layer. To match the most plausible candidates from all locations, we develop on an attention matcher based on the attention mechanism. The STTF-Recommender was evaluated with two real-world datasets, and the findings showed that STTF improves at least 13.75% in the mean value of the Recall index at different scales compared with the state-of-the-art models. Full article
(This article belongs to the Special Issue GIS Software and Engineering for Big Data)
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<p>Examples of trajectories showing the relation between non-consecutive visits and non-adjacent locations, the markers 1 through 5 are the most frequently visited locations by a user.</p>
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<p>The framework of the proposed STTF-Recommender. Spatio-Temporal embedding layer is used to encode user, location, and time from the historical trajectory into latent representations ①. Transformer aggregation layer is exploited to gather the locations of visits ② and update the hidden representation of each visit by stacking the Transformer layers so that our model can better mine the spatio-temporal relationship between non-adjacent locations and non-contiguous visits in the user trajectory sequence. Output layer is further divided into two modules: attention matcher and balance sampler, where attention matcher calculates the probability of each candidate location becoming the next visit location according to candidate location③, ④ and hidden representation of each visit ⑤. The balance sampler then calculates the cross-entropy loss using one positive sample and multiple negative samples⑥, ⑦.</p>
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<p>Transformer unit structure.</p>
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<p>Ablation Analysis by Comparing Different Modules in STTF-Recommender.</p>
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<p>The Impact of Different Time Scales.</p>
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<p>The sample map shows a sequence of locations that our model outputs. By examining the exact location in the Google Map, we found that location 2 is the New York Academy of Photography, other locations are very suitable for photography, for example, locations 1, 3, and 4 are parks, and location 5 is a Fine Arts Gallery. Although these locations are not adjacent to each other on the map, our model exploits the correlation between these locations.</p>
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30 pages, 9513 KiB  
Article
What Do We Know about Multidimensional Poverty in China: Its Dynamics, Causes, and Implications for Sustainability
by Jing He, Cheng Fu, Xiao Li, Fu Ren and Jiaxin Dong
ISPRS Int. J. Geo-Inf. 2023, 12(2), 78; https://doi.org/10.3390/ijgi12020078 - 20 Feb 2023
Cited by 10 | Viewed by 3544
Abstract
Poverty is a primary obstacle to achieving sustainable development. Therefore, exploring the spatiotemporal dynamics and causes of poverty is of great significance to the sustainable poverty reduction of the “post poverty alleviation era” in China. This paper used the multisource big data of [...] Read more.
Poverty is a primary obstacle to achieving sustainable development. Therefore, exploring the spatiotemporal dynamics and causes of poverty is of great significance to the sustainable poverty reduction of the “post poverty alleviation era” in China. This paper used the multisource big data of 2022 counties in China from 2000 to 2015 to establish a comprehensive evaluation framework to explore the multidimensional poverty situation in China. The results showed the following findings: There is an obvious spatiotemporal heterogeneity of multidimensional poverty, showing a typical stair-like gradient from high in the west to low in the east, with the poverty level in state-designated poverty counties higher and intensifying over time. The spatial differentiation of multidimensional poverty is contributed to by multiple factors, in which the geographical condition has a stronger impact on state-designated poverty counties, while natural endowment and human resources have a stronger effect on non-state-designated poverty counties. These things considered, the regional poverty causes were relatively stable before 2015, but the poverty spatial agglomeration of some regions in the Northwest, Northeast, and Yangtze River Economic Belt has undergone significant changes after 2015. These findings can help policymakers better target plans to eliminate various types of poverty in different regions. Full article
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<p>The geography of the 6 main regions and 832 state-designated poverty counties in China.</p>
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<p>Overall methodological framework.</p>
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<p>SOFM with <span class="html-italic">i</span> variables and the topology diagram in the 2−D Kohonen layer.</p>
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<p>Spatiotemporal pattern of the CMPI at five-year intervals from 2000 to 2015 (from (<b>a</b>–<b>d</b>), respectively). A higher value means a higher degree of poverty in the county. The black dash line is the Heihe−Tenchong Line (also known as the Hu Line), whose east part is the high population density area in China, while the west part is the low population density area.</p>
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<p>The spatiotemporal dynamics of the CMPI from 2000 to 2015 (<b>a</b>–<b>c</b>) show the changes of CMPI every five years from 2000 to 2015 respectively, and (<b>d</b>) shows the changes of CMPI from 2000 to 2015). A positive value (green block) indicates that the impact of the CMPI has increased compared to the previous stage.</p>
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<p>Violin plot of six PDFs in state-designated poverty counties and non-state-designated poverty counties: (<b>a</b>) <span class="html-italic">F</span><sub>1</sub>: Economic capital deprivation; (<b>b</b>) <span class="html-italic">F</span><sub>2</sub>: Geographical capital deprivation; (<b>c</b>) <span class="html-italic">F</span><sub>3</sub>: Natural resource endowment capital deprivation; (<b>d</b>) <span class="html-italic">F</span><sub>4</sub>: Agricultural capital deprivation; (<b>e</b>) <span class="html-italic">F</span><sub>5</sub>: Human and labor capital deprivation; and (<b>f</b>) <span class="html-italic">F</span><sub>6</sub>: Compulsory education deprivation. Lower values indicate better capital in that area and higher values indicate poorer capital.</p>
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<p>Violin plot of the CMPI in state-designated poverty counties and non-state-designated poverty counties.</p>
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<p>Interactive detection results of state-designated poverty counties in China from 2000 to 2015 (from <a href="#ijgi-12-00078-f004" class="html-fig">Figure 4</a>a–d, respectively): Gray indicates single factor action, Orange indicates bivariate enhancement, and Green indicates nonlinear enhancement. The value of the <span class="html-italic">q</span>-statistic was significant at 5% level.</p>
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<p>Interactive detection results in non-state-designated poverty counties in China from 2000 to 2015 (from <a href="#ijgi-12-00078-f004" class="html-fig">Figure 4</a>a–d, respectively): Gray indicates single factor action, Orange indicates bivariate enhancement, and Green indicates nonlinear enhancement. The value of the <span class="html-italic">q</span>-statistic was significant at 5% level.</p>
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<p>Categorized deprivation groups based on SOFM across China from 2000 to 2015: H is the high value interval of each PDF, L is the low value interval of each PDF, and M is the medium interval of each PDF.</p>
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<p>The 14 concentrated and contiguous poverty-stricken areas designated by the Chinese Central Government in 2012 (680 counties in total).</p>
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<p>Geographical Distribution Map of the Yangtze River Economic Belt.</p>
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15 pages, 3661 KiB  
Article
Trajectory Forecasting Using Graph Convolutional Neural Networks Based on Prior Awareness and Information Fusion
by Zhuangzhuang Yang, Chengxin Pang and Xinhua Zeng
ISPRS Int. J. Geo-Inf. 2023, 12(2), 77; https://doi.org/10.3390/ijgi12020077 - 20 Feb 2023
Cited by 1 | Viewed by 3341
Abstract
Predicting the future trajectories of multiple agents is essential for various applications in real life, such as surveillance systems, autonomous driving, and social robots. The trajectory prediction task is influenced by many factors, including individual historical trajectory, interactions between agents, and the fuzzy [...] Read more.
Predicting the future trajectories of multiple agents is essential for various applications in real life, such as surveillance systems, autonomous driving, and social robots. The trajectory prediction task is influenced by many factors, including individual historical trajectory, interactions between agents, and the fuzzy nature of an agent’s motion. While existing methods have made great progress on the topic of trajectory prediction, a lot of trajectory prediction methods take into account all pedestrians in the scene when simply modeling the influence of nearby pedestrians, and this inevitably brings redundant information. We propose a pedestrian trajectory prediction model based on prior awareness and information fusion. To make the input information more effective, for the different levels of importance of input trajectory information, we design a time information weighting module to weigh the observed trajectory information differently at different moments based on the original observed trajectory information. To reduce the impact of redundant information on trajectory prediction and to improve interaction between pedestrians, we present a spatial interaction module of multi-pedestrians and a topological graph fusion module. In addition, we use a temporal convolutional network module to obtain the temporal interactions between pedestrians. Compared to Social-STGCNN, the experimental results show that the model we propose reduces the average displacement error (ADE) and final displacement error (FDE) by 32% and 38% in the datasets of ETH and UCY, respectively. Moreover, based on this model, we design an autonomous driving obstacle avoidance system that can effectively ensure the safety of road pedestrians. Full article
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<p>The structure of the temporal information weighting module (TIW).</p>
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<p>Illustration of Spatial interaction of multi-pedestrians. (<b>a</b>), each pedestrian is considered independently as an aggregate; (<b>b</b>), three people are considered as an aggregate; (<b>c</b>), five people are considered as an aggregate.</p>
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<p>The structure of the spatial interaction module of multi-pedestrians.</p>
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<p>An illustration of the view diagram, “A–D” for four pedestrians, where the circle indicates the position of the pedestrian at the current moment, the dotted line indicates the boundary of the pedestrian’s view, the solid line indicates the movement direction of the pedestrians, and the blue and red lines indicate the influence vector between the <span class="html-italic">i</span>-th pedestrian, the <span class="html-italic">j</span>-th pedestrian, and the <span class="html-italic">k</span>-th pedestrian.</p>
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<p>An illustration of the directional graph, where the lines represent the direction of motion, circles and squares indicate the position of time <span class="html-italic">t</span> and <span class="html-italic">t</span> + 1, dashed lines indicate the spatial distance between pedestrians, and triangles indicate the existence of collision possibilities.</p>
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<p>The framework of the trajectory prediction model based on a prior awareness and information fusion, where TIW indicates the weighting module of temporal information, and the spatio-temporal Graph CNN contains the spatial interaction module of multi-pedestrians (M-PSI) that we proposed.</p>
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<p>The autonomous driving obstacle avoidance system is based on pedestrian trajectory prediction, where MDM indicates the module of mission decision-making, and PPM indicates the module of path planning.</p>
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<p>The effects of different improvement methods on five scenarios included in the datasets ETH and UCY, where the upper end of “I” denotes FDE and the lower end denotes ADE, and in the figure, different improvement methods are stacked in sequence.</p>
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<p>Comparison of the trajectory prediction of the model in this paper (<b>b</b>) with that of Social-STGCNN (<b>a</b>) in Hotel, where red dots indicate the observed location, blue dashed lines indicate the future real location, and yellow square dots indicate the predicted location based on the algorithm.</p>
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<p>Comparison of the trajectory prediction of the model in this paper with that of Social-STGCNN in multi-pedestrians gathering interaction.</p>
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21 pages, 15471 KiB  
Article
Urban Growth Forecast Using Machine Learning Algorithms and GIS-Based Novel Techniques: A Case Study Focusing on Nasiriyah City, Southern Iraq
by Sadeq Khaleefah Hanoon, Ahmad Fikri Abdullah, Helmi Z. M. Shafri and Aimrun Wayayok
ISPRS Int. J. Geo-Inf. 2023, 12(2), 76; https://doi.org/10.3390/ijgi12020076 - 20 Feb 2023
Cited by 1 | Viewed by 8268
Abstract
Land use and land cover changes driven by urban sprawl has accelerated the degradation of ecosystem services in metropolitan settlements. However, most optimisation techniques do not consider the dynamic effect of urban sprawl on the spatial criteria on which decisions are based. In [...] Read more.
Land use and land cover changes driven by urban sprawl has accelerated the degradation of ecosystem services in metropolitan settlements. However, most optimisation techniques do not consider the dynamic effect of urban sprawl on the spatial criteria on which decisions are based. In addition, integrating the current simulation approach with land use optimisation approaches to make a sustainable decision regarding the suitable site encompasses complex processes. Thus, this study aims to innovate a novel technique that can predict urban sprawl for a long time and can be simply integrated with optimisation land use techniques to make suitable decisions. Three main processes were applied in this study: (1) a supervised classification process using random forest (RF), (2) prediction of urban growth using a hybrid method combining an artificial neural network and cellular automata and (3) the development of a novel machine learning (ML) model to predict urban growth boundaries (UGBs). The ML model included linear regression, RF, K-nearest neighbour and AdaBoost. The performance of the novel ML model was effective, according to the validation metrics that were measured by the four ML algorithms. The results show that the Nasiriyah City expansion (the study area) is haphazard and unplanned, resulting in disastrous effects on urban and natural systems. The urban area ratio was increased by about 10%, i.e., from 2.5% in the year 1992 to 12.2% in 2022. In addition, the city will be expanded by 34%, 25% and 19% by the years 2032, 2042 and 2052, respectively. Therefore, this novel technique is recommended for integration with optimisation land use techniques to determine the sites that would be covered by the future city expansion. Full article
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<p>Flowchart of the methodology.</p>
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<p>Study area: Nasiriyah City, Iraq.</p>
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<p>LULC of the study area for 1992–2022: (<b>a</b>) LULC for 1992, (<b>b</b>) LULC for 2002, (<b>c</b>) LULC for 2012, (<b>d</b>) LULC for 2022.</p>
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<p>LULCC from 1922 to 2022: (<b>a</b>) area ratio of each class for the year 1992, (<b>b</b>) area ratio of land cover for the year 2002, (<b>c</b>) area ratio of land cover for the year 2012, (<b>d</b>) area ratio of land cover for the year 2022.</p>
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<p>Predicted LULC of the study area for the period 2032–2052: (<b>a</b>) prediction map of LULC for the year 2032, (<b>b</b>) prediction map of LULC for the year 2042, (<b>c</b>) LULC map for the year 2052.</p>
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<p>(<b>a</b>) Map of the study area showing the movement of UGBs for the following three decades; (<b>b</b>) zoomed-in map shows city expansion for years 2022, 2032, 2043 and 2052.</p>
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<p>(<b>a</b>) Location of pollution-causing zones and buffer zones and forecasted UGBs over time; (<b>b</b>) movement of UGBs from the limit buffer zone to the centres of the projects.</p>
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<p>Values of the coefficient of determination (R<sup>2</sup>) of the trained model measured by the four ML algorithms, RF, KNN, AB and LR, using validation and testing sets.</p>
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20 pages, 7254 KiB  
Article
Potential Loss of Ecosystem Service Value Due to Vessel Activity Expansion in Indonesian Marine Protected Areas
by Adam Irwansyah Fauzi, Nur Azizah, Emi Yati, Aulia Try Atmojo, Arif Rohman, Raden Putra, Muhammad Ario Eko Rahadianto, Desi Ramadhanti, Nesya Hafiza Ardani, Balqis Falah Robbani, Muhammad Ulin Nuha, Agung Mahadi Putra Perdana, Anjar Dimara Sakti, Muhammad Aufaristama and Ketut Wikantika
ISPRS Int. J. Geo-Inf. 2023, 12(2), 75; https://doi.org/10.3390/ijgi12020075 - 18 Feb 2023
Cited by 5 | Viewed by 3922
Abstract
Sustainable Development Goal (SDG) number 14 pertains to the preservation of sustainable marine ecosystems by establishing marine protected areas (MPAs). However, studies have reported massive damage to Indonesian marine ecosystems due to shipping pollution, anchors, and fishing nets. Thus, this study estimated the [...] Read more.
Sustainable Development Goal (SDG) number 14 pertains to the preservation of sustainable marine ecosystems by establishing marine protected areas (MPAs). However, studies have reported massive damage to Indonesian marine ecosystems due to shipping pollution, anchors, and fishing nets. Thus, this study estimated the potential loss of ecosystem service value due to vessel activity expansion in the MPAs of Indonesia. This study was divided into three stages. The first stage is vessel activity expansion zone modeling based on kernel density. The second stage is marine ecosystem service value modeling through semantic harmonization, reclassification, and spatial harmonization. The last stage is the overlay of the vessel expansion zone model, marine ecosystem service value model, and the MPA of Indonesia. The results of this study indicate that the marine neritic zone of Indonesia has an ecosystem service value of USD 814.23 billion, of which USD 159.87 billion (19.63%) are in the MPA. However, the increase in vessel activity that occurred in 2013–2018 could potentially lead to the loss of the ecosystem service value of USD 27.63 billion in 14 protected areas. These results can assist policymakers in determining priority conservation areas based on the threat of vessel activity and value of ecosystem services. Full article
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<p>Map presenting the Indonesian Fisheries Management Zone (IFMZ) and Indonesian marine protected areas (MPAs).</p>
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<p>Schematic depicting the research framework developed in this study.</p>
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<p>Map depicting the spatial model of marine ecosystem services value in the Indonesian neritic zone. (<b>A</b>) Aru Islands. (<b>B</b>) Nusa Tenggara Islands. (<b>C</b>) Southeast Sulawesi region.</p>
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<p>Plot illustrating the marine ecosystem services value in the Indonesian neritic zone by Indonesian Fisheries Management Zone (IFMZ or WPP-RI).</p>
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<p>Maps showing the vessel activity zone in the Indonesian Fisheries Management Zone (IFMZ or WPP-RI) in 2013 and 2018. (<b>A</b>) Vessel activity zone in 2013. (<b>B</b>) Vessel activity zone in 2018.</p>
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<p>Map and plot depicting the vessel expansion zone in the Indonesian Fisheries Management Zone (IFMZ) between 2013 and 2018.</p>
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<p>Pie chart illustrating the vessel expansion zone in the MPAs of Indonesia.</p>
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<p>Map showing the vessel expansion zone in 14 Indonesian MPAs.</p>
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18 pages, 5489 KiB  
Article
Developing and Disseminating a New Historical Geospatial Database from Kitchener’s 19th Century Map of Cyprus
by Christos Chalkias, Evangelos Papadias, Christoforos Vradis, Christos Polykretis, Kleomenis Kalogeropoulos, Athanasios Psarogiannis and Georgios Chalkias
ISPRS Int. J. Geo-Inf. 2023, 12(2), 74; https://doi.org/10.3390/ijgi12020074 - 18 Feb 2023
Cited by 5 | Viewed by 2558
Abstract
Extraction and dissemination of historical geospatial data from early maps are major goals of historical geographic information systems (HGISs) in the context of the spatial humanities. This paper illustrates the process of interpreting, georeferencing, organizing, and visualizing the content of a historical map [...] Read more.
Extraction and dissemination of historical geospatial data from early maps are major goals of historical geographic information systems (HGISs) in the context of the spatial humanities. This paper illustrates the process of interpreting, georeferencing, organizing, and visualizing the content of a historical map of Cyprus in the context of GISs and highlights the development of a national-scale spatial database of the island in the 19th century. This method was applied to Lord Kitchener’s historical map of Cyprus (published in 1885), which is considered the product of the first scientific topographic survey of Cyprus, is rich in geographic information about the area, and covers the entire island at a scale of 1:63,360. Previous attempts to create historical geodatabases have either focused on small areas or, when conducted on a national scale, have been thematically focused. The positional accuracy of the map was found to be 1.08 mm in map units, which was equivalent to 68.76 m on the ground. Accordingly, the main categories of geographic content (land cover, administrative units, settlements, transportation/communication networks, stream networks/water bodies, points of interest, annotations) were digitized from the georeferenced historical map. The Web-based application developed in this study supported the visualization of the historical geographic content of the map and its comparison with modern basemaps. The creation of the geodatabase presented in the study provides a template for similar studies and a basis for further development of the historical geodatabase of Cyprus. Full article
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<p>The 15 sheets of Kitchener’s map of Cyprus. The inset maps show details from the seamless mosaic (reproduced with the kind permission of the Sylvia Ioannou Charitable Foundation).</p>
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<p>The georeferencing workflow.</p>
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<p>The distribution of control points used in the georeferencing process.</p>
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<p>Various geospatial entities in the central plain of the island colored according to GIS layers: red polygons—settlements, green polygons—vineyards, pale green polygons—agricultural land, red lines—roads, blue lines—streams. Wells, ruins, windmills, and churches are also visible.</p>
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<p>The main screen of the Web application (<a href="https://kitchener.hua.gr/en" target="_blank">https://kitchener.hua.gr/en</a>, accessed on 10 January 2023).</p>
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24 pages, 11643 KiB  
Article
Exploring Spatiotemporal Patterns of Expressway Traffic Accidents Based on Density Clustering and Bayesian Network
by Yunfei Zhang, Fangqi Zhu, Qiuping Li, Zehang Qiu and Yajun Xie
ISPRS Int. J. Geo-Inf. 2023, 12(2), 73; https://doi.org/10.3390/ijgi12020073 - 18 Feb 2023
Cited by 3 | Viewed by 2551
Abstract
Exploring spatiotemporal patterns of traffic accidents from historic crash databases is one essential prerequisite for road safety management and traffic risk prevention. Presently, with the emergence of GIS and data mining technologies, numerous geospatial analysis methods have been successfully adopted for traffic accident [...] Read more.
Exploring spatiotemporal patterns of traffic accidents from historic crash databases is one essential prerequisite for road safety management and traffic risk prevention. Presently, with the emergence of GIS and data mining technologies, numerous geospatial analysis methods have been successfully adopted for traffic accident analysis. As characterized by high driving speeds, diverse vehicle types, and isolated traffic environments, expressways are confronted with more serious accident risks than urban roads. In this paper, we propose a combined method based on improved density clustering and the Bayesian inference network to explore spatiotemporal patterns of expressway accidents. Firstly, the spatiotemporal accident neighborhood is integrated into the DBSCAN clustering algorithm to discover multi-scale expressway black spots. Secondly, the Bayesian network model is separately employed in both local-scale black spots and regional-scale expressway networks to fully explore spatially heterogenous accident factors in various black spots and expressways. The experimental results show that the proposed method can correctly extract spatiotemporal aggregation patterns of multi-scale expressway black spots and meanwhile efficiently discover diverse causal factors for various black spots and expressways, providing a comprehensive analysis of accident prevention and safety management. Full article
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<p>Geo-referenced accident data.</p>
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<p>Spatiotemporal density-based accident clustering for black spot identification.</p>
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<p>Angle partitioning of month component of traffic accidents.</p>
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<p>Result of structure learning of accident Bayesian Network.</p>
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<p>Spatiotemporal distribution map of expressway accident data in Hunan Province during the period of 2012–2016.</p>
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<p>Results of identifying expressway accident-prone black spots in Hunan province, China.</p>
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<p>The satellite imagery and road facilities along black spot Changsha-Zhangjiajie expressway G5513 14–44 km.</p>
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<p>Statistical histogram of traffic accidents in Hunan sections of G4 expressway.</p>
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<p>Results comparison of the identified black spots on Beijing-Hongkong-Macao expressway using the accident data of 2012–2016 and 2018. (<b>a</b>) The identified black spots of Beijing-Hongkong-Macao expressway using 2012–2016 dataset. (<b>b</b>) The identified black spots of Beijing-Hongkong-Macao expressway using 2018 dataset.</p>
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<p>The satellite map and road facilities around black spots <span class="html-italic">i</span> and <span class="html-italic">j</span> in <a href="#ijgi-12-00073-f008" class="html-fig">Figure 8</a>a. (<b>a</b>) black spot <span class="html-italic">i</span>; (<b>b</b>) black spot <span class="html-italic">j</span>.</p>
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<p>Prior probabilities of all node variables for various black spots and the whole area. (<b>a</b>) Prior probabilities of all node variables for the whole expressway network. (<b>b</b>) Prior probabilities of all node variables for black spot G5513 14–44 km. (<b>c</b>) Prior probabilities of all node variables for black spot G4 1637–1668 km.</p>
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<p>Prior probabilities of all node variables for various black spots and the whole area. (<b>a</b>) Prior probabilities of all node variables for the whole expressway network. (<b>b</b>) Prior probabilities of all node variables for black spot G5513 14–44 km. (<b>c</b>) Prior probabilities of all node variables for black spot G4 1637–1668 km.</p>
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<p>Posterior probabilities when Extra-serious accidents happen in the whole area or at various black spots. (<b>a</b>) Posterior probabilities when Extra-serious accidents happen in the whole expressway network. (<b>b</b>) Posterior probabilities when Extra-serious accidents happen at black spot G5513 14–44 km. (<b>c</b>) Posterior probabilities when Extra-serious accidents happen at black spot G4 1637–1668 km.</p>
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<p>The increasing percentages (IP) of different node variables when Extra-serious accidents happen.</p>
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<p>Increasing percentage (ICP) of conditional probabilities under different combination of vehicle types, weather, and road types (SPC/MPC/LPC: Small/Middle/Large Passenger Car; LT/MT/HT: Light/Middle/Heavy Truck; PED: Pedestrian; other: other traffic modes; RS: Road Sections; RF: Road Facilities).</p>
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<p>Increasing percentage (ICP) of conditional probabilities under different combination of vehicle types, weather, and road types (SPC/MPC/LPC: Small/Middle/Large Passenger Car; LT/MT/HT: Light/Middle/Heavy Truck; PED: Pedestrian; other: other traffic modes; RS: Road Sections; RF: Road Facilities).</p>
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21 pages, 2667 KiB  
Article
Making Transportation Systems in U.S. Cities Smarter and More Inclusive: A Synthesis of Challenges and Evaluation of Strategies
by Chihuangji Wang, Fuzhen Yin, Yixuan Zhao and Li Yin
ISPRS Int. J. Geo-Inf. 2023, 12(2), 72; https://doi.org/10.3390/ijgi12020072 - 18 Feb 2023
Cited by 3 | Viewed by 2908
Abstract
Smart City (SC) strategies developed by local governments reflect how governments and planners envision SC and apply smart technologies, and what challenges they face and try to address. Little attention, however, has been given to investigating SC strategies or applications, especially in the [...] Read more.
Smart City (SC) strategies developed by local governments reflect how governments and planners envision SC and apply smart technologies, and what challenges they face and try to address. Little attention, however, has been given to investigating SC strategies or applications, especially in the U.S. context. Moreover, there is insufficient attention paid to whether SC strategies address social issues such as equity and public participatory opportunities. Based on the documentation from the U.S. Department of Transportation 2015 Smart City Challenge, we developed a framework to evaluate SC strategies on urban transportation systems using six standards: Safety, Mobility, Sustainability, Opportunity, Efficiency, and Equity. In addition, we synthesized the challenges U.S. smart cities encounter, and SC strategies proposed by local municipal governments to tackle them. Our findings show that most SC strategies aimed to improve Efficiency (78%) and Mobility (57%), while less attention has been given to providing Equity (8%) or Opportunity (7%). The most well-acknowledged challenge that the local governments face is the limited data and tools for decision-making, with 416 SC strategies (27%) proposed to address related issues. Our framework and results contribute to the future SC strategy evaluation and inclusive smart city development. Our study also identified a broad spectrum of available SC strategies planners and policymakers can refer to when designing an SC or overcoming SC challenges. Full article
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<p>Methodological flow chart.</p>
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<p>Percentage of SC strategies under six standards.</p>
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<p>Rank of SC proposals based on their level of balance on the six standards using Shannon entropy (seven finalist cities in the second round of SCC are marked with a black triangle).</p>
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<p>(<b>a</b>) Top five applicant cities with the highest entropy values using radar chart; (<b>b</b>) Bottom five applicant cities with the lowest entropy values using the radar chart; (<b>c</b>) Top ten SC proposals with the highest component score under the six standards (the black triangles denote the SC challenge finalists).</p>
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<p>(<b>a</b>) Distribution of 139 unique SC strategies under nine major challenge categories; (<b>b</b>) synthesis of 56 SC strategies under the corresponding challenges.</p>
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20 pages, 13337 KiB  
Article
A Contour Line Group Simplification Method Based on Classified Terrain Features
by Yuanfu Li, Qun Sun, Wenyue Guo, Qing Xu and Xinming Zhu
ISPRS Int. J. Geo-Inf. 2023, 12(2), 71; https://doi.org/10.3390/ijgi12020071 - 18 Feb 2023
Viewed by 1850
Abstract
Contour line group simplification methods can effectively preserve terrain features during map making and producing. This process involves two main steps, namely terrain feature line extraction and contour bend selection. The terrain feature line extraction includes two steps, that is, terrain feature point [...] Read more.
Contour line group simplification methods can effectively preserve terrain features during map making and producing. This process involves two main steps, namely terrain feature line extraction and contour bend selection. The terrain feature line extraction includes two steps, that is, terrain feature point extraction and classification, and terrain feature line connection. However, to date, many similar studies have not considered the hierarchy of terrain features. Therefore, we proposed a group simplification method for contour lines based on classified terrain features and tested it on a study area with mainly positive landforms. In accordance with geomorphological theory, we divided valleys into either gradually descending or ordinary. Valley points were extracted based on the constrained Delaunay triangulation method and then classified into the two categories. Gradually descending and ordinary valley lines were then connected. The contour bends were grouped based on the valley lines extracted and then selected according to the geometric indicators of the bend group. The results have demonstrated that the valley lines extracted closely matched human perception in integrity and structure. Contour lines simplified by our method achieved effective reduction of map information and adequate retention of the main terrain structures, which are similar to those from manual simplification. Full article
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<p>Water erosion evolution. H and L indicate the upper and lower points of the water flow path, respectively. a–f indicate the edges (colored orange) of the water flow path. Blue arrows indicate the evolution of the water confluence line.</p>
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<p>An example of a gradually descending valley and an ordinary valleys using 3-dimentional modeling.</p>
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<p>Framework of the proposed method.</p>
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<p>Valley bend, valley point, and end point of the valley bend.</p>
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<p>Valley point extraction.</p>
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<p>Gradually descending valley edge corrections. The maximum moveable length of the midpoint of the gradually descending valley edge is <math display="inline"><semantics> <mrow> <msub> <mi>l</mi> <mi>S</mi> </msub> </mrow> </semantics></math>.</p>
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<p>Ordinary valley line connection process.</p>
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<p>Examples of two types of bottom points: (<b>a</b>) bottom point on a closed contour line; (<b>b</b>) bottom point on an open contour line.</p>
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<p>Example of a redundant valley line. V<sub>1</sub>–V<sub>9</sub> are the valley points extracted in previous step.</p>
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<p>Three indicators of the geometric features of valleys. <math display="inline"><semantics> <mi>A</mi> </semantics></math> is the area of the region that is colored green.</p>
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<p>Valley line extraction results from the method proposed in this study.</p>
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<p>Valley line extraction results from the method proposed by Zhang et al. [<a href="#B19-ijgi-12-00071" class="html-bibr">19</a>].</p>
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<p>Enlarged view of Zones D and E from <a href="#ijgi-12-00071-f011" class="html-fig">Figure 11</a>. The numbers in (<b>b</b>) indicate the elevation of the contour line.</p>
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<p>Contour line simplification results.</p>
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<p>Local simplification results of: (<b>a</b>) the method proposed in this study; (<b>b</b>) the Douglas–Peucker algorithm.</p>
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<p>Local simplification results of: (<b>a</b>) the proposed method; (<b>b</b>) the bend selection algorithm.</p>
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<p>Results of the proposed method and those of manual simplification.</p>
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29 pages, 5753 KiB  
Article
A Comparison of Cartographic and Toponymic Databases in a Multilingual Environment: A Methodology for Detecting Redundancies Using ETL and GIS Tools
by Oihana Mitxelena-Hoyos and José-Lázaro Amaro-Mellado
ISPRS Int. J. Geo-Inf. 2023, 12(2), 70; https://doi.org/10.3390/ijgi12020070 - 18 Feb 2023
Cited by 2 | Viewed by 2403
Abstract
Toponymy, a transversal discipline for geography, linguistics, and history, finds one of its main supports in cartography. Due to exhaustiveness on the territory, cadastral cartography and its toponymy have the ideal characteristics to develop systematic geographical analyses. Moreover, cadastre and geographical names are [...] Read more.
Toponymy, a transversal discipline for geography, linguistics, and history, finds one of its main supports in cartography. Due to exhaustiveness on the territory, cadastral cartography and its toponymy have the ideal characteristics to develop systematic geographical analyses. Moreover, cadastre and geographical names are part of the geographic reference data according to Annex 1 of the INSPIRE directive. This work presents the design, implementation, and application of a methodology based on Geographic Information Systems and Extract, Transform, and Load (ETL) tools for detecting coincidences between the cadastral geoinformation and the official gazetteer corresponding to the province of Gipuzkoa, Spain. Methodologically, this study proposes a solution to the issues raised by bilingualism in the study area. This problem is approached a priori, in the previous data treatment, and a posteriori, applying semantic criteria. The results show a match between the datasets of close to 40%. In this way, the uniqueness and richness of the analyzed source and its outstanding contribution to the potential integration of the official toponymic corpus are evidenced. Full article
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<p>The geographical extent of the research (province of Gipuzkoa, Spain). Source: Own elaboration from <a href="http://www.ign.es" target="_blank">www.ign.es</a> (accessed on 22 November 2022). Frame coordinates in km.</p>
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<p>Flowchart with the process undertaken.</p>
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<p>Location map of the sample municipalities. Frame coordinates in km.</p>
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<p>Cadastral parcels selected by supervision (5C+ matching). Frame coordinates in km.</p>
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<p>Cadastral parcels selected automatically (5C+ matching). Frame coordinates in km.</p>
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<p>Cadastral parcels selected by supervision (4C and 5C+ matching). Frame coordinates in km.</p>
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<p>Cadastral parcels selected automatically (4C and 5C+ matching). Frame coordinates in km.</p>
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<p>Omission and commission errors in the selected cadastral parcels. Frame coordinates in km.</p>
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<p>Results from the proposed method to the whole province of Gipuzkoa. Frame coordinates in km.</p>
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19 pages, 29396 KiB  
Article
Multi-Source Data and Machine Learning-Based Refined Governance for Responding to Public Health Emergencies in Beijing: A Case Study of COVID-19
by Demiao Yu, Xiaoran Huang, Hengyi Zang, Yuanwei Li, Yuchen Qin and Daoyong Li
ISPRS Int. J. Geo-Inf. 2023, 12(2), 69; https://doi.org/10.3390/ijgi12020069 - 14 Feb 2023
Viewed by 2080
Abstract
The outbreak of COVID-19 in Beijing has been sporadic since the beginning of 2022 and has become increasingly severe since October. In China’s policy of insisting on dynamic clearance, fine-grained management has become the focus of current epidemic prevention and control. In this [...] Read more.
The outbreak of COVID-19 in Beijing has been sporadic since the beginning of 2022 and has become increasingly severe since October. In China’s policy of insisting on dynamic clearance, fine-grained management has become the focus of current epidemic prevention and control. In this paper, we conduct a refined COVID-19 risk prediction and identification of its influencing factors in Beijing based on neighborhood-scale spatial statistical units. We obtained geographic coordinate data of COVID-19 cases in Beijing and quantified them into risk indices of each statistical unit. Additionally, spatial autocorrelation was used to analyze the epidemic risk clustering characteristics. With the multi-source data, 20 influencing elements were constructed, and their spatial heterogeneity was explored by screening 8 for Multiscale Geographically weighted regression (MGWR) model analysis. Finally, a neural network classification model was used to predict the risk of COVID-19 within the sixth ring of Beijing. The MGWR model and the neural network classification model showed good performance: the R2 of the MGWR model was 0.770, and the accuracy of the neural network classification model was 0.852. The results of this study show that: (1) COVID-19 risk is uneven, with the highest clustering within the Fifth Ring Road of Beijing; (2) The results of the MGWR model show that population structure, population density, road density, residential area density, and living service facility density have significant spatial heterogeneity on COVID-19 risk; and (3) The prediction results show a high COVID-19 risk, with the most severe risk being in the eastern, southeastern and southern regions. It should be noted that the prediction results are highly consistent with the current epidemic situation in Shijingshan District, Beijing, and can provide a strong reference for fine-grained epidemic prevention and control in Beijing. Full article
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<p>Project framework and workflow.</p>
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<p>Study area of this paper.</p>
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<p>Graphical representation of COVID-19 risk statistics.</p>
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<p>Neural network classification model. (Note:The same color represents the same set of parameters for the same set of neural networks.)</p>
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<p>Results of spatial autocorrelation analysis: (<b>a</b>) Results of Moran’s 1 spatial autocorrelation analysis; (<b>b</b>) LISA analysis results.</p>
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<p>The spatial distribution of R-squared values from the MGWR model.</p>
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<p>Spatial distribution of the MGWR local coefficients.</p>
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<p>This is a figure. Schemes follow the same formatting.</p>
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<p>MGWR local coefficient kriging interpolation analysis results.</p>
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<p>MGWR local coefficient kriging interpolation analysis results.</p>
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3 pages, 196 KiB  
Editorial
Climate Change Adaptation: The Role of Geospatial Data in Sustainable Infrastructures
by Cesar Casiano Flores and Joep Crompvoets
ISPRS Int. J. Geo-Inf. 2023, 12(2), 68; https://doi.org/10.3390/ijgi12020068 - 14 Feb 2023
Cited by 1 | Viewed by 2445
Abstract
Climate change is a challenging reality, making adaptation at local, national and international levels a crucial need [...] Full article
20 pages, 7087 KiB  
Article
Overview of Lightning Trend and Recent Lightning Variability over Sri Lanka
by Vindhya Kalapuge, Dilaj Maduranga, Niranga Alahacoon, Mahesh Edirisinghe, Rushan Abeygunawardana and Manjula Ranagalage
ISPRS Int. J. Geo-Inf. 2023, 12(2), 67; https://doi.org/10.3390/ijgi12020067 - 13 Feb 2023
Cited by 2 | Viewed by 3941
Abstract
The study was conducted to analyze spatial and temporal variations of lightning activity over Sri Lanka and the surrounding coastal belt region bounded by 5.75–10.00 N and 79.50–89.00 E. Flash data collected by the Lightning Imaging Sensor (LIS) on NASA’s Tropical Rainfall Measuring [...] Read more.
The study was conducted to analyze spatial and temporal variations of lightning activity over Sri Lanka and the surrounding coastal belt region bounded by 5.75–10.00 N and 79.50–89.00 E. Flash data collected by the Lightning Imaging Sensor (LIS) on NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite from 1998 to 2014 and the Lightning Imaging Sensor placed on the International Space Station (ISS) from 2018 to 2021 were used for the study. The Mann-Kendall test and Sen’s slope estimator were applied to annual and seasonal lightning data from 1998 to 2014 to identify the trends in the TRMM dataset. A positive slope of 0.23 was obtained for annual flash densities, while a slope of 0.956 was obtained for First Inter-Monsoon (FIM) seasonal data. Considering the ISS data, the annual variation of lightning activity in 2020 displays the lowest flash density, whereas the highest is represented in 2019 with a value of 10.48 flashes km−2 year−1. The highest mean flash density is observed in Colombo in 2019 at a value of 34.85 flashes km−2 year−1. Overall, April displayed the highest annual flash distribution from 2018 to 2021, whereas the second peak was mostly viewed around September and November. All districts have displayed a significant amount of lightning during April for the period 2018 to 2021. FIM displayed the highest lightning distribution over the country. When considering the seasonal variation, districts belonging to the wet zone and intermediate zone displayed most flashes during the FIM. Full article
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<p>Study area indicating climatic zones, district boundaries, and administrative divisions of Sri Lanka.</p>
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<p>Methodology flow chart of the study.</p>
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<p>All island seasonal variation of mean lightning flash densities from 1998–2014.</p>
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<p>All island monthly lightning flash distribution from 1998 to 2014.</p>
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<p>All island yearly variations from 2018–2021.</p>
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<p>(<b>a</b>–<b>d</b>) represent district-level annual variation of lightning flash densities in 2018, 2019, 2020, and 2021 respectively.</p>
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<p>All island monthly variation from 2018–2021.</p>
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<p>(<b>a</b>–<b>d</b>) represent the district-wise monthly variation of lightning flash densities from 2018 to 2021, respectively.</p>
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<p>All island seasonal variations of light flash distribution from 2018–2021.</p>
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<p>2018–2021 monsoon season variation during FIM, SWM, SIM, and NEM.</p>
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<p>The annual trend line from 1998 to 2014.</p>
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<p>Yearly forecasted values from 2015 to 2021.</p>
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<p>The trend line for FIM from 1998 to 2014.</p>
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<p>Lightning flash densities forecasted for FIM from 2015 to 2021.</p>
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<p>District-level Sen’s slope (colour gradient) and Kendall’s Tau values (numbers) for four seasons, FIM, SWM, SIM and NEM, represented by (<b>a</b>–<b>d</b>), respectively.</p>
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17 pages, 7240 KiB  
Article
Influencing Pedestrians’ Route Choice Using Route Shape Simplification
by Peng Ti, Ruyu Dai, Fangyi Wan, Tao Xiong, Hao Wu and Zhilin Li
ISPRS Int. J. Geo-Inf. 2023, 12(2), 66; https://doi.org/10.3390/ijgi12020066 - 12 Feb 2023
Cited by 2 | Viewed by 2019
Abstract
Pedestrians’ route choice is critical for several purposes, while deliberately changing map representations can influence map users’ route choice. Simplifying routes’ geometric shapes is one way to achieve this. However, the other geometric characteristics of routes (e.g., the relative distance of different routes, [...] Read more.
Pedestrians’ route choice is critical for several purposes, while deliberately changing map representations can influence map users’ route choice. Simplifying routes’ geometric shapes is one way to achieve this. However, the other geometric characteristics of routes (e.g., the relative distance of different routes, differences in initial orientation, the number of intersections, and the direction changes) also influence pedestrians’ route choice, per relevant research. Hence, this study conducted an experimental investigation to examine the influence of route shape simplification on pedestrians’ route choice, under various geometric characteristics conditions. The results of the statistical tests and correlation analyses showed that (1) route shape simplification has a significant influence on route choice; (2) larger relative distance and direction changes reduce shape simplification’s influence, while the number of intersections and differences in initial orientation have weak effects; (3) 1.3 times the relative distance may be the threshold for the selection of recommended routes, and the improvement of visual continuity at route nodes may prove more influential. The results of this study can support the applicability of shape simplification to influence route choice. Full article
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<p>Route shape simplification. (<b>a</b>) Line shape simplification using direction distortion. (<b>b</b>) Example of a route’s shape simplification.</p>
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<p>The seven baseline maps used in this study.</p>
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<p>Route choice results for the baseline maps.</p>
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<p>The baseline maps with recommended routes and baseline routes.</p>
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<p>The baseline maps with recommended routes and baseline routes.</p>
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<p>Four modified maps of the recommended routes after shape simplification.</p>
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<p>Route choice results for the modified maps.</p>
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<p>Differences in the choice percentages of the recommended routes with different initial orientations.</p>
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<p>Differences in the choice percentages of the recommended routes with a different number of intersections.</p>
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<p>Differences in the choice percentages of the recommended routes with different relative distances.</p>
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<p>Differences in the choice percentages of the recommended routes with different angular step depths.</p>
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<p>Two simplified routes with larger angular step depths and lower choice percentages.</p>
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26 pages, 3301 KiB  
Article
Co-Creating GIS-Based Dashboards to Democratize Knowledge on Urban Resilience Strategies: Experience with Camerino Municipality
by Maria Luisa Villani, Sonia Giovinazzi and Antonio Costanzo
ISPRS Int. J. Geo-Inf. 2023, 12(2), 65; https://doi.org/10.3390/ijgi12020065 - 12 Feb 2023
Cited by 7 | Viewed by 2783
Abstract
Natural hazards are increasingly threatening our communities; hence it is imperative to provide communities with reliable information on possible impacts of such disasters, and on resilience measures that can be adopted to recover from disasters. To increase the engagement of various stakeholders in [...] Read more.
Natural hazards are increasingly threatening our communities; hence it is imperative to provide communities with reliable information on possible impacts of such disasters, and on resilience measures that can be adopted to recover from disasters. To increase the engagement of various stakeholders in decision-making processes related to resilience to natural hazards, problem-specific information needs to be presented to them in a language understandable to non-experts in the field. To this end, this paper illustrates experimentation with low-code platforms for fast digitalization of resilience reports, incorporating the perspectives of various stakeholders in the analysis, thus making informed decision-making practicable. We present a co-creation-based approach to develop GIS-based user-friendly dashboards in support to the identification of resilience strategies against natural hazards; this approach has been developed within the framework of the European project ARCH. Urban areas are regarded as complex social-ecological systems whose various dimensions should be considered in this resilience endeavor, during all phases of the Disaster Risk Reduction and Climate Change Adaptation cycle. The work presented in this paper specifically targets the possible impacts and risks that might affect the cultural heritage subsystems of our cities, generally underrepresented in the international literature related to urban resilience assessment. We describe how we applied our approach to the Camerino municipality, a historic Italian town exposed to seismic risk, which was struck by a severe earthquake sequence in 2016–2017 and discuss the results of our experience. Full article
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<p>Illustration of the ARCH DRR/CCA framework [<a href="#B2-ijgi-12-00065" class="html-bibr">2</a>] with the activities addressed by the ARCH DSS tool.</p>
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<p>ARCH DSS agile development model, encompassing co-creation activities, ARCH HArIS and THIS and the ARCH DSS hosted in a low-code environment for business intelligence.</p>
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<p>Schematic representation of the co-created impact and risk assessment process that has been originally defined as part of the ARCH project.</p>
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<p>Data model represented as a UML class diagram. The yellow color highlights the risk/resilience variables and definitions that are used to evaluate the scenarios (how). The Scenario-Results entity is a container for the Hazard-Scenario values, Exposure/Vulnerability values and the computed Impacts (what). Location refers to the geographic place of the objects exposed at risk (where) and Time to the time periods of reference for the scenarios (when), * stands for multiplicity.</p>
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<p>On-line interactive board used to support co-creation related to the ARCH DSS Camerino activities in particular during Workshops W2 and W3.</p>
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<p>Visualization of ex ante impact scenarios.</p>
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<p>Comparative Visualization of ex ante and ex-post impact scenarios: the effective of implementing a resilience option can be seen and compared with as-built scenarios.</p>
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<p>Comparative Visualization of ex post impact scenarios of two different resilience options so that their different effectiveness can be seen and compared.</p>
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18 pages, 343 KiB  
Review
Self-Supervised Representation Learning for Geographical Data—A Systematic Literature Review
by Padraig Corcoran and Irena Spasić
ISPRS Int. J. Geo-Inf. 2023, 12(2), 64; https://doi.org/10.3390/ijgi12020064 - 12 Feb 2023
Cited by 3 | Viewed by 3176
Abstract
Self-supervised representation learning (SSRL) concerns the problem of learning a useful data representation without the requirement for labelled or annotated data. This representation can, in turn, be used to support solutions to downstream machine learning problems. SSRL has been demonstrated to be a [...] Read more.
Self-supervised representation learning (SSRL) concerns the problem of learning a useful data representation without the requirement for labelled or annotated data. This representation can, in turn, be used to support solutions to downstream machine learning problems. SSRL has been demonstrated to be a useful tool in the field of geographical information science (GIS). In this article, we systematically review the existing research literature in this space to answer the following five research questions. What types of representations were learnt? What SSRL models were used? What downstream problems were the representations used to solve? What machine learning models were used to solve these problems? Finally, does using a learnt representation improve the overall performance? Full article
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<p>A taxonomy of SSRL models, adopted from that proposed by Deldari et al. [<a href="#B13-ijgi-12-00064" class="html-bibr">13</a>].</p>
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<p>A taxonomy of geographical data types is displayed.</p>
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6 pages, 397 KiB  
Article
Matching Standard and Secant Parallels in Cylindrical Projections
by Miljenko Lapaine
ISPRS Int. J. Geo-Inf. 2023, 12(2), 63; https://doi.org/10.3390/ijgi12020063 - 11 Feb 2023
Cited by 2 | Viewed by 1633
Abstract
Map projections are usually interpreted by mapping a sphere onto an auxiliary surface, and then the surface is developed into a plane. It is taken as a fact without proof that the parallels in which the auxiliary surface intersects the sphere are mapped [...] Read more.
Map projections are usually interpreted by mapping a sphere onto an auxiliary surface, and then the surface is developed into a plane. It is taken as a fact without proof that the parallels in which the auxiliary surface intersects the sphere are mapped without distortions. In a previous paper, based on a theoretical consideration and illustrated with several examples, the author concluded that explaining cylindrical projections as mapping onto a cylindrical surface is not a good approach, because it leads to misunderstanding important properties of projection. In this paper I prove that there are no equal-area, equidistant, or conformal cylindrical projections for which the standard parallel will coincide with secant parallel after folding the map into a cylinder. Full article
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<p>Map in a normal aspect cylindrical projection bent into a cylinder surface that intersects a sphere of radius 1, <span class="html-italic">r</span> is the cylinder radius, <span class="html-italic">v</span> is the height of secant parallel above the plane of the equator.</p>
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17 pages, 13972 KiB  
Article
Where Am I Now? Modelling Disorientation in Pan-Scalar Maps
by Guillaume Touya, Maïeul Gruget and Ian Muehlenhaus
ISPRS Int. J. Geo-Inf. 2023, 12(2), 62; https://doi.org/10.3390/ijgi12020062 - 10 Feb 2023
Cited by 4 | Viewed by 3526
Abstract
Disorientation is a common feeling for all users of zoomable multi-scale maps, even for those with good orientation and spatial skills. We make the assumption that this problem is mainly due to the desert fog effect, documented in human–computer interaction within multi-scale zoomable [...] Read more.
Disorientation is a common feeling for all users of zoomable multi-scale maps, even for those with good orientation and spatial skills. We make the assumption that this problem is mainly due to the desert fog effect, documented in human–computer interaction within multi-scale zoomable environments. Starting with a collection of reported experiences of disorientation, this paper explores this notion from the spatial cognition, philosophical and human–computer interaction perspectives and proposes a model of disorientation in the exploration of multi-scale maps. We argue that disorientation is a problem of reconciliation between the current map view and the mental map of the user, where landmarks visible on the map or memorised in the mental map play a key role. The causes for failed reconciliation are discussed and illustrated by our collected experiences of disorientation. Full article
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<p>Maps of Kobe at different scales from Google Maps, showing the differences that cause the desert fog effect.</p>
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<p>Simplified version of the cartographic communication model by Kolacny [<a href="#B9-ijgi-12-00062" class="html-bibr">9</a>].</p>
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<p>Zoomed-in view of the Berlin memorial of the Soviet War on top and a view at a smaller scale, where the Y-shaped river section can be used to find the memorial (source: Google).</p>
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<p>Illustration of the spatial distortion effect with a mental representation of Saint-Brévin, France on the left and the corresponding map extract on the right (©OpenStreetMap contributors).</p>
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<p>The map that caused the France and Italy border disorientation experience, where the border is the wide pink line (source: IGN).</p>
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<p>On the left is the OSM map that caused the trust disorientation experience, with the quay that is now pedestrian still represented as a secondary road. In the Google map, the quay is correctly represented as a pedestrian road (source: Google and OpenStreetMap contributors).</p>
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<p>A pan-scalar map exploration to search for the train station of La Baule in France. The exploration was composed of phases where the user inspected map views and transition phases between two map views (source: OpenStreetMap contributors).</p>
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<p>Reconciliation model of (dis)orientation during the exploration of pan-scalar maps. At each new view, the spatial working memory connects and reconciles the content of the map view with the mental representation of space, which is temporarily enriched by the previous views visited in the exploration path.</p>
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<p>Illustration of the reconciliation process (i.e., locating the map view within one’s mental map).</p>
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<p>Three examples illustrating the pre-attentive mode of reconciliation. (<b>a</b>) The sea is a clear Gestalt element that enables a pre-attentive reconciliation (source: IGN). (<b>b</b>) Some touristic venues of Paris are highlighted with symbols that are very salient compared with the map background (source: Google Maps). (<b>c</b>) This cluttered map limits any pre-attentive reconciliation due to the amount of rendered information (source: OpenStreetMap contributors).</p>
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<p>Two examples where a failed anticipation might occur. (<b>a</b>) The Gestalt principle of closure anticipates a ring road around the town of Chateaubriant, France, whereas it only covers three fourth of the extent. (<b>b</b>) The water surface in the coastal town of La Grande Motte, France seems to be the Mediterranean Sea, but it is a lake, and the sea shore is just south of this place (©OpenStreetMap contributors).</p>
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<p>Two consecutive scales at zoom levels 14 and 15 where the map changes a lot, preventing pre-attentive reconciliation based on common landmarks (source: IGN).</p>
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25 pages, 21829 KiB  
Article
BiodivAR: A Cartographic Authoring Tool for the Visualization of Geolocated Media in Augmented Reality
by Julien Mercier, Nicolas Chabloz, Gregory Dozot, Olivier Ertz, Erwan Bocher and Daniel Rappo
ISPRS Int. J. Geo-Inf. 2023, 12(2), 61; https://doi.org/10.3390/ijgi12020061 - 9 Feb 2023
Cited by 5 | Viewed by 3124
Abstract
Location-based augmented reality technology for real-world, outdoor experiences is rapidly gaining in popularity in a variety of fields such as engineering, education, and gaming. By anchoring medias to geographic coordinates, it is possible to design immersive experiences remotely, without necessitating an in-depth knowledge [...] Read more.
Location-based augmented reality technology for real-world, outdoor experiences is rapidly gaining in popularity in a variety of fields such as engineering, education, and gaming. By anchoring medias to geographic coordinates, it is possible to design immersive experiences remotely, without necessitating an in-depth knowledge of the context. However, the creation of such experiences typically requires complex programming tools that are beyond the reach of mainstream users. We introduce BiodivAR, a web cartographic tool for the authoring of location-based AR experiences. Developed using a user-centered design methodology and open-source interoperable web technologies, it is the second iteration of an effort that started in 2016. It is designed to meet needs defined through use cases co-designed with end users and enables the creation of custom geolocated points of interest. This approach enabled substantial progress over the previous iteration. Its reliance on geolocation data to anchor augmented objects relative to the user’s position poses a set of challenges: On mobile devices, GNSS accuracy typically lies between 1 m and 30 m. Due to its impact on the anchoring, this lack of accuracy can have deleterious effects on usability. We conducted a comparative user test using the application in combination with two different geolocation data types (GNSS versus RTK). While the test’s results are undergoing analysis, we hereby present a methodology for the assessment of our system’s usability based on the use of eye-tracking devices, geolocated traces and events, and usability questionnaires. Full article
(This article belongs to the Special Issue Cartography and Geomedia)
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<p>The <span class="html-italic">BioSentiers</span> location-based AR application. The species presented were prepared by a biologist so as to create an educational trail for pupils in a natural reserve. A video showing the application in use during a field trip is available on a Zenodo publicly accessible repository <a href="https://zenodo.org/record/6501843" target="_blank">https://zenodo.org/record/6501843</a> (accessed on 28 December 2022).</p>
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<p>Use Cases: system’s scope, end users and their interactions with the system, main expected scenarios and the goals that the system may help end users achieve.</p>
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<p>Screenshots of the prototype made with ARIS. Location-trigger POIs prompt dialogs with fictional characters who send users on missions to go explore newly appeared POIs on the map. When reaching the POIs’ location, users either had to listen to sounds, identify or photograph a specimen, or watch a video before returning to the character to earn a reward.</p>
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<p>Teachers watching a video in AR about a plant species, overlaying a visual marker placed next to a specimen.</p>
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<p>UX/UI designers and developers during an ideation session.</p>
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<p>The <span class="html-italic">BiodivAR</span> concept: the mobile AR interface allows on-site, spatial interaction with media anchored to geographic coordinates. The desktop interface displays the same geodata on a 2D interactive map (leaflet). GeoJSON data can be imported or exported.</p>
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<p><span class="html-italic">BiodivAR</span> structure and dependencies. The user interfaces (desktop and mobile) are managed by the Vue.js framework, which sends a request to a Rest API built with hapi.js. The Rest API gets the requested data from an SQLite database through a Prisma.js object–relational mapping (ORM). The mobile and desktop 2D interactive maps are powered by the Leaflet.js library and the AR cameras and objects are managed by the WebXR API, the three.js 3D library and the A-Frame framework, with the LBAR.js [<a href="#B48-ijgi-12-00061" class="html-bibr">48</a>] additional custom library we designed to power geolocated POIs. All of theses dependencies are open-source.</p>
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<p>A view of <span class="html-italic">BiodivAR</span>’s desktop user interface with its main features highlighted. Various types of geodata (POIs, traces, events) may be displayed on the map by toggling them on their respective tabs.</p>
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<p>The POI editor appears when a POI is created or edited. It lets users manage and customize POIs. Users can upload media (3D models, pictures, sound, or plain text) and position them in the embedded 3D scene preview. Each media may be assigned individual behaviors so that they appear at specific user-triggered events.</p>
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<p><span class="html-italic">BiodivAR</span>’s mobile user interface: (<b>a</b>) login; (<b>b</b>) all available bioverses sorted by categories (authored by user, public, bookmarked); (<b>c</b>) AR view after opening a bioverse; (<b>d</b>) a collapsible 2D map for navigation; (<b>e</b>) view of a media showing the distribution map of an adjacent specimen’s species, after entering a POI’s radius.</p>
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<p><span class="html-italic">BiodivAR</span>’s data structure: The <span class="html-italic">Bioverse</span> table in the center contains all the other elements and notably <span class="html-italic">POIs</span>, which contain one <span class="html-italic">Coordinate</span> and <span class="html-italic">n Media</span>.</p>
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<p>RTK geolocation data integration from the Ardusimple RTK kit to a mobile device. This diagram details the setup for real-time kinematic positioning: A reference/base station broadcasts correction data (RTCM raw format) through an NTRIP caster to an NTRIP client (mobile application). The data are integrated by the multi-GNSS receiver, which corrects most of the GNSS biases, resulting in centimeter-accurate geolocation. The Funduino processor broadcasts the geolocation data (3DOF) to the mobile device through a Bluetooth module.</p>
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<p>Comparative user test design: an experimental group used the <span class="html-italic">BiodivAR</span> application for 15 min in combination with RTK data while the control group used it with GNSS data. Various data were collected during and after the test to help observe the impact of geolocation data on usability.</p>
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13 pages, 2272 KiB  
Article
Using HyperLogLog to Prevent Data Retention in Social Media Streaming Data Analytics
by Marc Löchner and Dirk Burghardt
ISPRS Int. J. Geo-Inf. 2023, 12(2), 60; https://doi.org/10.3390/ijgi12020060 - 9 Feb 2023
Cited by 1 | Viewed by 2367
Abstract
Social media data are widely used to gain insights about social incidents, whether on a local or global scale. Within the process of analyzing and evaluating the data, it is common practice to download and store it locally. Considerations about privacy protection of [...] Read more.
Social media data are widely used to gain insights about social incidents, whether on a local or global scale. Within the process of analyzing and evaluating the data, it is common practice to download and store it locally. Considerations about privacy protection of social media users are often neglected thereby. However, protecting privacy when dealing with personal data is demanded by laws and ethics. In this paper, we introduce a method to store social media data using the cardinality estimator HyperLogLog. Based on an exemplary disaster management scenario, we show that social media data can be analyzed by counting occurrences of posts, without becoming in possession of the actual raw data. For social media data analyses like these, that are based on counting occurrences, cardinality estimation suffices the task. Thus, the risk of abuse, loss, or public exposure of the data can be mitigated and privacy of social media users can be preserved. The ability to do unions and intersections on multiple datasets further encourages the use of this technology. We provide a proof-of-concept implementation for our introduced method, using data provided by the Twitter API. Full article
(This article belongs to the Special Issue Trustful and Ethical Use of Geospatial Data)
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<p>Social media data processing graph. (<b>a</b>) Example post. (<b>b</b>) The post’s social, temporal, spatial (green), and topical data, and its hidden unique ID (red). (<b>c</b>) Encode the corresponding geohash from the geo-coordinates. The result represents the area plotted by the rectangle over the outlines of Dresden. (<b>d</b>) Store the post ID in the HLL set of the database record matching the geohash.</p>
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<p>Exemplary structure of a database table that stores all data referring to the pre-defined term <tt>flood</tt>. It shows four records, each stands for one area represented by the geohash, and the corresponding HLL set containing the post IDs.</p>
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<p>Visualizing the cardinality of posts containing (<b>a</b>) the term <tt>omicron</tt> spelled with a C, (<b>b</b>) <tt>omikron</tt> spelled with a K, and (<b>c</b>) the union of the sets, per area defined by geohash precision 4. The union of the two datasets helps to understand that the early 2022 variant of COVID-19 is a trending topic in more areas than what a consideration of each individual set suggests. Data from Twitter, January through March 2022. Classification: Head/Tail Breaks [<a href="#B48-ijgi-12-00060" class="html-bibr">48</a>].</p>
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<p>Post cardinality gain. The table on the left shows the cardinality gain per hour and its rate accordingly. The chart on the right shows the chart visualization of the table. It outlines the threshold through the dotted line at 500 posts per hour. The attention sign highlights the exceeding cardinality gain rate and, thus, marks the point of alert.</p>
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14 pages, 5189 KiB  
Article
Examining the Nonlinear Impacts of Origin-Destination Built Environment on Metro Ridership at Station-to-Station Level
by Ben Liu, Yunfei Xu, Sizhen Guo, Mingming Yu, Ziyue Lin and Hong Yang
ISPRS Int. J. Geo-Inf. 2023, 12(2), 59; https://doi.org/10.3390/ijgi12020059 - 9 Feb 2023
Cited by 6 | Viewed by 2309
Abstract
Although many studies have explored the relationship between the built environment and metro ridership, the literature offers limited evidence on the nonlinear effect of origin and destination built environments on station-to-station ridership. Using data from Chongqing, this study uses the gradient boosting decision [...] Read more.
Although many studies have explored the relationship between the built environment and metro ridership, the literature offers limited evidence on the nonlinear effect of origin and destination built environments on station-to-station ridership. Using data from Chongqing, this study uses the gradient boosting decision trees (GBDT) model to explore the nonlinear impact of origin and destination built environments on metro ridership. The research results show that the built environment at the origin has a greater impact on metro ridership than the built environment at the destination. All the independent variables examined have complex nonlinear effects and threshold effects on metro ridership. The distance to the city center, the number of companies, and the building volume rate have a greater positive effect on metro ridership, both at the origin and at the destination. The research results provide suggestions for optimizing the built environment around metro stations. Full article
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<p>Study area.</p>
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<p>Nonlinear impact of built environment on metro ridership. (<b>a</b>) Distance to the city center (origin). (<b>b</b>) Number of companies (origin). (<b>c</b>) Floor area ratio (destination). (<b>d</b>) Floor area ratio (origin). (<b>e</b>) Number of companies (destination). (<b>f</b>) Distance to the city center (destination). (<b>g</b>) Transfer station (origin). (<b>h</b>) Transfer station (destination).</p>
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<p>Nonlinear impact of built environment on metro ridership. (<b>a</b>) Distance to the city center (origin). (<b>b</b>) Number of companies (origin). (<b>c</b>) Floor area ratio (destination). (<b>d</b>) Floor area ratio (origin). (<b>e</b>) Number of companies (destination). (<b>f</b>) Distance to the city center (destination). (<b>g</b>) Transfer station (origin). (<b>h</b>) Transfer station (destination).</p>
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16 pages, 2579 KiB  
Article
Mini-Map Design Features as a Navigation Aid in the Virtual Geographical Space Based on Video Games
by Krzysztof Zagata and Beata Medyńska-Gulij
ISPRS Int. J. Geo-Inf. 2023, 12(2), 58; https://doi.org/10.3390/ijgi12020058 - 8 Feb 2023
Cited by 9 | Viewed by 4594
Abstract
The main objective of this study is to identify features of mini-map design as a navigational aid in the virtual geographical space in 100 popular video games for a computer platform. The following research methods were used: visual comparative analysis, classification and selection [...] Read more.
The main objective of this study is to identify features of mini-map design as a navigational aid in the virtual geographical space in 100 popular video games for a computer platform. The following research methods were used: visual comparative analysis, classification and selection of cartographic material, comparison of specific parameters for selected features of design elements, and application of cartographic design rules and popularity of design solutions in video games. The study revealed eight features of mini-map design and their popular parameters and attributes in video games, with only one game meeting all conditions of popularity: projection: orthographic; centring: player-centred; base layers: artificial; shape: circle; orientation: camera view; position: bottom left; proportions: 2.1–3%; additional navigational element: north arrow. The key attributes of the mini-map’s features were captured, which, when considered separately, complementarily and potentially holistically, confirm the possibility of designing the mini-map according to traditional cartographic design principles. The identified parameters of the mini-map can be useful not only in the design of the game cartography interface, but also for other geomedia products. Full article
(This article belongs to the Special Issue Cartography and Geomedia)
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<p>Examples of video games with a mini-map in the game cartography interface (<b>A</b>) Red Dead Redemption 2; (<b>B</b>) Guild Wars 2; (<b>C</b>) Cyberpunk 2077.</p>
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<p>Parameters and attributes for 8 mini-map features according to the chosen 100 video games ((<b>A</b>) shape, (<b>B</b>) position, (<b>C</b>) orientation, (<b>D</b>) centring, (<b>E</b>) projection, (<b>F</b>) base layers, (<b>G</b>) proportions, (<b>H</b>) additional navigational elements).</p>
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<p>The percentage of use of a specific parameter of the mini-map with examples of video games according to their majority unambiguity. Bold red stands for the highest percentage, solid red for a value close to the highest, blue colour for values far from the highest. * One video game can use many additional navigational elements.</p>
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<p>Mini-map composition on the display view (16:9) with the most popular parameters of 8 design features—by separate analysis for each parameter.</p>
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<p>Grouping of the most popular and preferred parameters of the mini-map features: projection, centring, base layers and shape with separate addition of other popular attributes or parameters from four other features (see <a href="#ijgi-12-00058-f003" class="html-fig">Figure 3</a>).</p>
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20 pages, 8438 KiB  
Article
Estimation of Travel Cost between Geographic Coordinates Using Artificial Neural Network: Potential Application in Vehicle Routing Problems
by Keyju Lee and Junjae Chae
ISPRS Int. J. Geo-Inf. 2023, 12(2), 57; https://doi.org/10.3390/ijgi12020057 - 8 Feb 2023
Cited by 3 | Viewed by 1977
Abstract
The vehicle routing problem (VRP) attempts to find optimal (minimum length) routes for a set of vehicles visiting a set of locations. Solving a VRP calls for a cost matrix between locations. The size of the matrix grows quadratically with an increasing number [...] Read more.
The vehicle routing problem (VRP) attempts to find optimal (minimum length) routes for a set of vehicles visiting a set of locations. Solving a VRP calls for a cost matrix between locations. The size of the matrix grows quadratically with an increasing number of locations, restricting large-sized VRPs from being solved in a reasonable amount of time. The time needed to obtain a cost matrix is expensive when routing engines are used, which solve shortest path problems in the back end. In fact, details on the shortest path are redundant; only distance or time values are necessary for VRPs. In this study, an artificial neural network (ANN) that receives two geo-coordinates as input and provides estimated cost (distance and time) as output is trained. The trained ANN model was able to estimate with a mean absolute percentage error of 7.68%, surpassing the quality of 13.2% with a simple regression model on Euclidean distance. The possibility of using a trained model in VRPs is examined with different implementation scenarios. The experimental results with VRPs confirm that using ANN estimation instead of Euclidean distance produces a better solution, which is verified to be statistically significant. The results also suggest that an ANN can be a better choice than routing engines when the trade-off between response time and solution quality is considered. Full article
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<p>Latitude and longitude bound for the distance and time sampling.</p>
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<p>Converting randomly generated points to the closest POIs. (<b>a</b>) Random origin–destination points. (<b>b</b>) Converted points.</p>
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<p>The ANN structure used for training.</p>
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<p>Absolute Percentage error of estimation in box whisker plot. (<b>a</b>) Regression model. (<b>b</b>) Artificial neural network model.</p>
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<p>Percentage error of estimation in box whisker plot. (<b>a</b>) Regression model. (<b>b</b>) Artificial neural network model.</p>
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<p>Frequency of estimations being wrong is closeness measure. (<b>a</b>) Distance measure. (<b>b</b>) Time measure.</p>
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<p>Magnitude of estimations being wrong in closeness measure. (<b>a</b>) Distance measure. (<b>b</b>) Time measure.</p>
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<p>Correctness rate of selecting closest neighbors using estimated distance. (<b>a</b>) Number of nodes = 100. (<b>b</b>) Number of nodes. = 500. (<b>c</b>) Number of nodes = 1000.</p>
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<p>Correctness rate of selecting closest neighbors using estimated time. (<b>a</b>) Number of nodes = 100. (<b>b</b>) Number of nodes = 500. (<b>c</b>) Number of nodes = 1000.</p>
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<p>An Illustration of Large Neighborhood Search Algorithm. (<b>a</b>) Before removal. (<b>b</b>) After removal (destroy). (<b>c</b>) After repair.</p>
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<p>Solution time and gap for experimental scenarios with cost matrix type of distance. (<b>a</b>) Problem size: 100, LNS iteration: 1000. (<b>b</b>) Problem size: 100, LNS iteration: 5000. (<b>c</b>) Problem size: 500, LNS iteration: 1000. (<b>d</b>) Problem size: 500, LNS iteration: 5000. (<b>e</b>) Problem size: 1000, LNS iteration: 1000. (<b>f</b>) Problem size: 1000, LNS iteration: 5000.</p>
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<p>Solution time and gap for experimental scenarios with cost matrix type of distance. (<b>a</b>) Problem size: 100, LNS iteration: 1000. (<b>b</b>) Problem size: 100, LNS iteration: 5000. (<b>c</b>) Problem size: 500, LNS iteration: 1000. (<b>d</b>) Problem size: 500, LNS iteration: 5000. (<b>e</b>) Problem size: 1000, LNS iteration: 1000. (<b>f</b>) Problem size: 1000, LNS iteration: 5000.</p>
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<p>Solution time and gap for experimental scenarios with cost matrix type of time. (<b>a</b>) Problem size: 100, LNS iteration: 1000. (<b>b</b>) Problem size: 100, LNS iteration: 5000. (<b>c</b>) Problem size: 500, LNS iteration: 1000. (<b>d</b>) Problem size: 500, LNS iteration: 5000. (<b>e</b>) Problem size: 1000, LNS iteration: 1000. (<b>f</b>) Problem size: 1000, LNS iteration: 5000.</p>
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<p>Solution time and gap for experimental scenarios with cost matrix type of time. (<b>a</b>) Problem size: 100, LNS iteration: 1000. (<b>b</b>) Problem size: 100, LNS iteration: 5000. (<b>c</b>) Problem size: 500, LNS iteration: 1000. (<b>d</b>) Problem size: 500, LNS iteration: 5000. (<b>e</b>) Problem size: 1000, LNS iteration: 1000. (<b>f</b>) Problem size: 1000, LNS iteration: 5000.</p>
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17 pages, 69177 KiB  
Article
Crowd Density Estimation and Mapping Method Based on Surveillance Video and GIS
by Xingguo Zhang, Yinping Sun, Qize Li, Xiaodi Li and Xinyu Shi
ISPRS Int. J. Geo-Inf. 2023, 12(2), 56; https://doi.org/10.3390/ijgi12020056 - 8 Feb 2023
Cited by 7 | Viewed by 4619
Abstract
Aiming at the problem that the existing crowd counting methods cannot achieve accurate crowd counting and map visualization in a large scene, a crowd density estimation and mapping method based on surveillance video and GIS (CDEM-M) is proposed. Firstly, a crowd semantic segmentation [...] Read more.
Aiming at the problem that the existing crowd counting methods cannot achieve accurate crowd counting and map visualization in a large scene, a crowd density estimation and mapping method based on surveillance video and GIS (CDEM-M) is proposed. Firstly, a crowd semantic segmentation model (CSSM) and a crowd denoising model (CDM) suitable for high-altitude scenarios are constructed by transfer learning. Then, based on the homography matrix between the video and remote sensing image, the crowd areas in the video are projected to the map space. Finally, according to the distance from the crowd target to the camera, the camera inclination, and the area of the crowd polygon in the geographic space, a BP neural network for the crowd density estimation is constructed. The results show the following: (1) The test accuracy of the CSSM was 96.70%, and the classification accuracy of the CDM was 86.29%, which can achieve a high-precision crowd extraction in large scenes. (2) The BP neural network for the crowd density estimation was constructed, with an average error of 1.2 and a mean square error of 4.5. Compared to the density map method, the MAE and RMSE of the CDEM-M are reduced by 89.9 and 85.1, respectively, which is more suitable for a high-altitude camera. (3) The crowd polygons were filled with the corresponding number of points, and the symbol was a human icon. The crowd mapping and visual expression were realized. The CDEM-M can be used for crowd supervision in stations, shopping malls, and sports venues. Full article
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<p>Flowchart of the CDEM-M.</p>
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<p>Flowchart of crowd geographic mapping.</p>
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<p>Flowchart of the CNPM.</p>
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<p>The structure of the CNPM.</p>
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<p>Schematic diagram of three model factors of a crowd polygon.</p>
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<p>Schematic diagram of the crowd map visualization.</p>
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<p>The 2D map of the experimental area.</p>
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<p>Crowd semantic segmentation.</p>
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<p>Crowd noise removal.</p>
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<p>Crowd geographic mapping.</p>
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<p>Chart of predicted value and true value of crowd counting.</p>
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<p>Crowd detection results in dense scenes: (<b>a</b>) the CDEM-M; (<b>b</b>) the SFCN+ algorithm.</p>
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<p>Crowd visualization: (<b>a</b>) crowd polygon; (<b>b</b>) crowd map visualization.</p>
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20 pages, 18367 KiB  
Article
Revealing the Impact of COVID-19 on Urban Residential Travel Structure Based on Floating Car Trajectory Data: A Case Study of Nantong, China
by Fei Tao, Junjie Wu, Shuang Lin, Yaqiao Lv, Yu Wang and Tong Zhou
ISPRS Int. J. Geo-Inf. 2023, 12(2), 55; https://doi.org/10.3390/ijgi12020055 - 8 Feb 2023
Cited by 4 | Viewed by 2160
Abstract
The volume of residential travel with different purposes follows relatively stable patterns in a specific period and state; therefore, it can reflect the operating status of urban traffic and even indicate urban vitality. Recent research has focused on changes in the spatiotemporal characteristics [...] Read more.
The volume of residential travel with different purposes follows relatively stable patterns in a specific period and state; therefore, it can reflect the operating status of urban traffic and even indicate urban vitality. Recent research has focused on changes in the spatiotemporal characteristics of urban mobility affected by the pandemic but has rarely examined the impact of COVID-19 on the travel conditions and psychological needs of residents. To quantitatively assess travel characteristics during COVID-19, this paper proposed a method by which to determine the purpose of residential travel by combining urban functional areas (UFAs) based on machine learning. Then, the residential travel structure, which includes origin–destination (OD) points, residential travel flow, and the proportion of flows for different purposes, was established. Based on taxi trajectory data obtained during the epidemic in Nantong, China, the case study explores changes in travel flow characteristics under the framework of the residential travel structure. Through comparison of the number and spatial distribution of OD points in the residential travel structure, it is found that residential travel hotspots decreased significantly. The ratios of commuting and medical travel increased from 43.8% to 45.7% and 7.1% to 8.1%, respectively. Conversely, the ratios of other travel types all decreased sharply. Moreover, under Maslow’s hierarchy of needs model, further insights into the impacts of COVID-19 on changes in residential psychological needs are discussed in this paper. This work can provide a reference for decision makers to cope with the change in urban traffic during a public health emergency, which is beneficial to the sustainable healthy development of cities. Full article
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<p>Study area. (<b>a</b>) Chongchuan District and marked points with attributes of UFAs, (<b>b</b>) map of China, (<b>c</b>) Nantong City.</p>
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<p>Framework of this paper. Marked points represent the points with urban functional area attributes; OD flow represents the origin–destination flow.</p>
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<p>Identification of attributes of UFAs. (<b>a</b>) Residential area. (<b>b</b>) Shopping mall. (<b>c</b>) Hospital. (<b>d</b>) School. (<b>e</b>) Traffic center. (<b>f</b>) Scenic spot. UFAs refer to the urban functional areas.</p>
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<p>Monthly change in residential travel volume.</p>
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<p>Daily change in residential travel volume.</p>
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<p>Major events during the transmission period of COVID-19.</p>
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<p>Urban hotspots of residential travel in (<b>a</b>) normal period of society, (<b>b</b>) early period of COVID-19, (<b>c</b>) outbreak period of COVID-19, (<b>d</b>) rework period of society, and (<b>e</b>) recovery period of society.</p>
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<p>The density of O points around each UFA in (<b>a</b>) normal period of society, (<b>b</b>) early period of COVID-19, (<b>c</b>) outbreak period of COVID-19, (<b>d</b>) rework period of society, and (<b>e</b>) recovery period of society. O point represents the origin point in one trajectory of residential travel. Marked points were obtained from the center points of UFAs. The size of the grid is 1 km × 1 km.</p>
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<p>The density of D points around each UFA in (<b>a</b>) normal period of society, (<b>b</b>) early period of COVID-19, (<b>c</b>) outbreak period of COVID-19, (<b>d</b>) rework period of society, and (<b>e</b>) recovery period of society. D point represents the destination point in one trajectory of residential travel. Marked points were obtained from the center points of UFAs. The size of the grid is 1 km × 1 km.</p>
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<p>Residential travel flow in (<b>a</b>) normal period of society, (<b>b</b>) early period of COVID-19, (<b>c</b>) outbreak period of COVID-19, (<b>d</b>) rework period of society, and (<b>e</b>) recovery period of society.</p>
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<p>NFR of UFAs in (<b>a</b>) normal period of society, (<b>b</b>) early period of COVID-19, (<b>c</b>) outbreak period of COVID-19, (<b>d</b>) rework period of society, and (<b>e</b>) recovery period of society. NFR represents the net flow rate. UFAs represent urban functional areas.</p>
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<p>The ratios of residential travel with different purposes over different periods. Period 1 represents the normal period of society. Period 2 represents the early period of COVID-19. Period 3 represents the outbreak period of COVID-19. Period 4 represents the rework period of society. Period 5 represents the recovery period of society.</p>
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<p>Classification of residential travel according to Maslow’s hierarchy of needs.</p>
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<p>Thematic map of the classified POI data.</p>
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23 pages, 28368 KiB  
Article
Interactive Web Mapping Applications for 2D and 3D Geo-Visualization of Persistent Scatterer Interferometry SAR Data
by Panagiotis Kalaitzis, Michael Foumelis, Christos Vasilakos, Antonios Mouratidis and Nikolaos Soulakellis
ISPRS Int. J. Geo-Inf. 2023, 12(2), 54; https://doi.org/10.3390/ijgi12020054 - 7 Feb 2023
Cited by 3 | Viewed by 2489
Abstract
Surface motion is a complex, dynamic phenomenon that draws significant scientific attention. This study focuses on the development of a cartographic toolset for the visualization of space-borne Persistent Scatterer Interferometry (PSI) surface motion measurements. The entire archive of Sentinel-1 Synthetic Aperture Radar (SAR) [...] Read more.
Surface motion is a complex, dynamic phenomenon that draws significant scientific attention. This study focuses on the development of a cartographic toolset for the visualization of space-borne Persistent Scatterer Interferometry (PSI) surface motion measurements. The entire archive of Sentinel-1 Synthetic Aperture Radar (SAR) imagery over the broader Thessaloniki (Greece) area has been exploited to derive the PSI measurements utilizing the Surface motioN mAPPING (SNAPPING) service on the Geohazards Exploitation Platform (GEP). A collection of web map applications, interactive visualization tools, and an animated map were developed based on state-of-the-art approaches. This geo-visualization toolset consists of the following: (i) Three web map applications exploring PSI velocity rates, PSI time series, and a comparison of PSI with geodetic leveling data; (ii) Two interactive map tools focusing on 3D visualization of PSI time series and estimating velocity rates for predefined temporal frames; and (iii) An animated map of PSI time series. The utilization of the aforementioned visualization toolset provided useful conclusions about the variety of land displacement that occurs in different subareas of Northern Greece from different causes. More specifically, certain subareas with significant subsidence rates range from −2 mm/year up to −18 mm/year from 2015 to 2020. The magnitude of displacement and the underlying causes (subsidence, faults, landslides, human processes, etc.) varies across different subareas. On the other hand, a subarea of uplift trend exists in the north of the city of Thessaloniki with displacements up to 5 mm/year for the period between 2015–2020, despite being constrained by the fact that the geo-visualization platform is able to display SNAPPING PSI measurements from any location around the world, making it a useful tool for global exploration. The platform’s contents are available through a user-friendly graphical interface and are mostly addressed to domain experts as well as end-users. Opposed to similar approaches where static 2D maps and velocity rates web applications are presented through this platform, users can monitor and study the dynamic behavior of surface motion to a spatiotemporal extent more thoroughly. Full article
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<p>Area of interest located in the north part of Greece, referring to land included within the red line, bounding box. Base map source: Esri, GEBCO, DeLorme, NaturalVue, Garmin, FAO, NOAA, USGS.</p>
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<p>Workflow of methodology followed for the integration of the research.</p>
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<p>Categorization of the nine different prefixed cartographic scales used for presenting PSI data.</p>
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<p>All five cartographic techniques i.e. (<b>a</b>) stretched, (<b>b</b>) equal interval (one mm/year for each class), (<b>c</b>) natural breaks, (<b>d</b>) equal interval (two mm/year for each class) and (<b>e</b>) quantiles were evaluated on the same dataset. Cartographic results are presented respectively by their velocity values contributions and color pallets.</p>
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<p>Animation map, with all PSI time series displacement values, presented from 2015 to 2020 in the broader area of Thessaloniki Region. Date presented here is 21 January 2019.</p>
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<p>PSI velocity rates from 2015 to 2020 in the broader area of Thessaloniki International Airport, northern Greece. Velocity rates range from 4.0 to −18.0 mm/year and refer to points that are located over buildup areas.</p>
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<p>Subareas of (1) Sindos–Kalochori–Chalastra region, (2) the NW part of lake Koronia lake (3) the broader area of Thessaloniki airport and (4) the broader area of Moudania region with negative displacement velocity rates from 2015 up to 2020. Base map source: Esri, DeLorme, NaturalVue.</p>
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<p>Evolution of deformation web map application, presenting deformation values of unique dates (in mm) in a subarea NW of Koroneia lake.</p>
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<p>PSI vs. leveling method comparison web application, with two datasets of points depicted over Sindos region.</p>
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<p>Example of displacement trends comparison via graphs, between PSI time series data (point A) and leveling data (point B), for the same time frame. Graph (<b>A</b>) shows subsidence trend from 17 June 2018 to 6 July 2019, relative stability trend from 6 July 2019 to 15 November 2019, and an uplift trend from 15 November 2019 to 27 December 2020. Graph (<b>B</b>) shows a subsidence trend from 15 June 2018 to 15 June 2019 and an uplift trend from 15 June 2019 to 15 June 2020.</p>
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<p>A presentation of 3D visualization of PSI time series displacement values in Sindos Region from 2015 to 2020. The value for each date is presented as a tile in space. The orientation of image (<b>a</b>) is SE to NW, while that of image (<b>b</b>) is SN.</p>
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<p>Tiles of displacement values after selection of time and value range. Values between 19 January 2017 and 9 April 2019, ranging from −19.1 mm to −4.8 mm, are presented in this example.</p>
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<p>In image (<b>A</b>), a chart of the evolution of displacement values for one specific point is presented for the period between May 2015 and November 2020. All selected displacement values of the point are presented in blue color on the 3D map. In image (<b>B</b>), multiple selections of points (their displacement values) and dates are selected and presented on the chart, from March 2018 until June 2020. Displacement values of each selected record are depicted by different colored lines on the graph.</p>
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<p>Mean velocity rates of Sindos region have been estimated and visualized for the period between 2015 and 2020. A graph of the PSI time series displacement values but also mean velocity is presented by the linear regression line for the selected record in the SE.</p>
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<p>Geo-visualization toolset of all six cartographic elements created.</p>
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20 pages, 45679 KiB  
Article
Multi-Temporal Sentinel-1 SAR and Sentinel-2 MSI Data for Flood Mapping and Damage Assessment in Mozambique
by Manuel Nhangumbe, Andrea Nascetti and Yifang Ban
ISPRS Int. J. Geo-Inf. 2023, 12(2), 53; https://doi.org/10.3390/ijgi12020053 - 7 Feb 2023
Cited by 13 | Viewed by 3626
Abstract
Floods are one of the most frequent natural disasters worldwide. Although the vulnerability varies from region to region, all countries are susceptible to flooding. Mozambique was hit by several cyclones in the last few decades, and in 2019, after cyclones Idai and Kenneth, [...] Read more.
Floods are one of the most frequent natural disasters worldwide. Although the vulnerability varies from region to region, all countries are susceptible to flooding. Mozambique was hit by several cyclones in the last few decades, and in 2019, after cyclones Idai and Kenneth, the country became the first one in southern Africa to be hit by two cyclones in the same raining season. Aiming to provide the local authorities with tools to yield better responses before and after any disaster event, and to mitigate the impact and support in decision making for sustainable development, it is fundamental to continue investigating reliable methods for disaster management. In this paper, we propose a fully automated method for flood mapping in near real-time utilizing multi-temporal Sentinel-1 Synthetic Aperture Radar (SAR) data acquired in the Beira municipality and Macomia district. The procedure exploits the processing capability of the Google Earth Engine (GEE) platform. We map flooded areas by finding the differences of images acquired before and after the flooding and then use Otsu’s thresholding method to automatically extract the flooded area from the difference image. To validate and compute the accuracy of the proposed technique, we compare our results with the Copernicus Emergency Management Service (Copernicus EMS) data available in the study areas. Furthermore, we investigated the use of a Sentinel-2 multi-spectral instrument (MSI) to produce a land cover (LC) map of the study area and estimate the percentage of flooded areas in each LC class. The results show that the combination of Sentinel-1 SAR and Sentinel-2 MSI data is reliable for near real-time flood mapping and damage assessment. We automatically mapped flooded areas with an overall accuracy of about 87–88% and kappa of 0.73–0.75 by directly comparing our prediction and Copernicus EMS maps. The LC classification is validated by randomly collecting over 600 points for each LC, and the overall accuracy is 90–95% with a kappa of 0.80–0.94. Full article
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<p>Mozambican map with the city of Beira and the Mocomia district highlighted. The base map is the open street map obtained from Qgis plugins.</p>
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<p>A 90 m resolution USGS digital elevation model (DEM) of the Beira municipality with all its 26 neighborhoods. It can be seen that the center of the city (area indicated by the arrow) is located in a low elevation area.</p>
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<p>City of Beira after TC Idai on 18 March 2019, and the Macomia district after TC Kenneth on 27 April 2019. (<b>a</b>) Beira. <a href="https://bergensia.com/red-cross-90-percent-of-beira-in-mozambique-destroyed-by-cyclone-idai/" target="_blank">https://bergensia.com/red-cross-90-percent-of-beira-in-mozambique-destroyed-by-cyclone-idai/</a>, Accessed: 31 May 2020. (<b>b</b>) Macomia. Available online: <a href="https://www.nbcnews.com/news/world/incredibly-difficult-aid-workers-reach-mozambique-cyclone-survivors-n1000081" target="_blank">https://www.nbcnews.com/news/world/incredibly-difficult-aid-workers-reach-mozambique-cyclone-survivors-n1000081</a>, Accessed: 17 November 2020.</p>
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<p>Red points on the left image are examples of GPS points that we collected during the field work in Beira. The label WTR2 stands for point 2 of water, GLA12 stands for point 12 of grass land, and CH1 stands for point 1 of houses in Chota Neighborhood. The right image corresponds to the point HC1 and illustrates some damaged classrooms of a public school in this neighborhood.</p>
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<p>Copernicus EMS maps for Beira on 16 March 2019 (<b>a</b>), and for Macomia on 1 May 2019 (<b>b</b>). <a href="https://emergency.copernicus.eu/mapping/list-of-activations-rapid" target="_blank">https://emergency.copernicus.eu/mapping/list-of-activations-rapid</a>, Accessed: 20 July 2022. (<b>a</b>) Beira. (<b>b</b>) Macomia.</p>
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<p>Flowchart summarizing the work in this project.</p>
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<p>FM results for TCs Idai, Kenneth, and Eloise. (<b>a</b>) displays FM results for two consecutive days in Beira. It can be seen that on 20th the water tends to be receding. (<b>a</b>) TC Idai. (<b>b</b>) TC Kenneth. (<b>c</b>) TC Eloise.</p>
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<p>(<b>a</b>) displays an RGB image comprising the S2 bands 8A, 11, and 12. (<b>b</b>) shows the corresponding pan-sharpening results. (<b>a</b>) RGB images with the bands 8A, 11 and 12 before pan sharpening. (<b>b</b>) RGB images after pan-sharpening.</p>
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<p>Classification results in Beira and its surroundings. On the left we can see the original image and on the right the respective classification results. (<b>a</b>) S2 image, 2 December 2018. (<b>b</b>) Classification results.</p>
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<p>Classification results in Macomia. On the left we can see the original image, and on the right the respective classification results. (<b>a</b>) S2 image, 2 December 2018. (<b>b</b>) Classification results.</p>
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<p>Classification results only for the city of Beira (municipality of Beira) including its 26 neighborhoods.</p>
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