CN113096389A - Multi-source data-based national highway network topology construction method - Google Patents

Abstract

The invention provides a national highway network topology construction method based on multi-source data. The method comprises the following steps: collecting multi-source data required for constructing national highway network topology, wherein the multi-source data comprises national highway toll station GIS data, national highway road GIS data and national provincial data; unifying longitude and latitude coordinate systems of a plurality of data sources, and performing space-time matching on the plurality of data sources; simplifying and combining the GIS data of national highway roads; and performing fusion matching on the GIS data of the highway toll station, the China provincial data and the simplified and combined GIS data of the highway road, and constructing a national highway network topology based on the fused multi-source data. The invention fully utilizes multi-source data, comprehensively considers the information integrity and the structural simplicity of the network topology of the expressway, constructs the network topology based on the grade separation, the toll station and the bidirectional road of the expressway, and has simple algorithm and easy implementation.

Description

Multi-source data-based national highway network topology construction method

Technical Field

The invention relates to the technical field of highway management, in particular to a national highway network topology construction method based on multi-source data.

Background

By 2019, the highway mileage in China is close to 15 kilometers, and the lane mileage reaches 67 kilometers, so that the method makes a very important contribution to the rapid development of the economy in China. However, the provincial toll station, as a key component of the highway system, often becomes a congestion bottleneck of the highway, and the provincial toll station often has a large charging congestion condition during the peak time of travel, thereby seriously affecting transportation and public travel. China completely cancels highway provincial toll stations in 2020, and marks that highway toll management formally enters a network integrated operation stage.

The expressway network topology refers to the distribution and connection state of all toll stations and cross points among networks consisting of main roads, ramps, toll stations and cross points of the expressway. The construction of the topological network is to express the network of the entity as a data model by a certain method. Before a provincial toll station is cancelled, the toll operation is carried out on the expressway in China by taking provinces as units, namely, closed networking type toll collection is adopted for the travel in the provinces; when the vehicle is going out across provinces, the vehicle is respectively parked and charged in each province, and the inter-province clearing problem does not exist. However, after the provincial toll station is cancelled, all expenses of the whole trip are collected across the last province of the provincial trip, and then the expenses are cleared and settled to each province, so that the problem of provincial clearance exists. The construction of the network topology of the expressway is a basic condition for solving the problems of provincial cost clearing, traffic path identification and the like based on a theoretical method. Under the condition, the national highway topological network is scientifically constructed by adopting the existing road traffic data, and the method has important significance for highway network integrated operation management.

The existing research on the topology of the highway network is divided into two types: one is to select a small-range local expressway network to construct a topology, and the local topology cannot be used for the national provincial clearing problem because the information of the provincial toll stations is not complete; the other electronic Map is constructed based on a GIS or Map and contains highway network topology information, and the electronic Map is not suitable for a complex sorting algorithm due to the fact that the electronic Map contains too many details such as ramps, entrance and exit toll lanes and the like. Under the background of national highway integrated operation, large-scale network topology is required for nationwide liquidation, and the utilization of multi-source data is difficult to avoid. The topology for constructing the large-scale network faces the problems of difficulty in obtaining source data, normative difference of the multi-source data, efficiency of processing and analyzing algorithms and the like, and the problems bring certain challenges for efficiently constructing the topology of the highway network.

Disclosure of Invention

The embodiment of the invention provides a national highway network topology construction method based on multi-source data, which aims to overcome the problems in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme.

A national highway network topology construction method based on multi-source data comprises the following steps:

collecting multi-source data required for constructing national highway network topology, wherein the multi-source data comprises national highway toll station GIS data, national highway road GIS data and national provincial data;

unifying longitude and latitude coordinate systems of a plurality of data sources, and performing space-time matching on the plurality of data sources;

simplifying and combining the GIS data of national highway roads;

and performing fusion matching on the GIS data of the highway toll station, the China provincial data and the simplified and combined GIS data of the highway road, and constructing a national highway network topology based on the fused multi-source data.

Preferably, the GIS data of the national highway toll station is point data which comprises toll station numbers, toll station serial numbers, toll station names for short, provinces, toll station types and toll station longitude and latitude field information; the national highway GIS data is line data which comprises road numbers, road names, road lengths, city codes, head end point numbers, tail end point numbers, head end point longitudes and latitudes and field information of tail end point longitudes and latitudes; the Chinese provincial data is point data and comprises provincial point numbers, provinces, province numbers, longitude and latitude fields.

Preferably, the method further comprises: identifying the positions of missing data and error data in the multi-source data, judging the feature information of the missing data and the error data, crawling supplementary data from an online map by Python software according to the feature information, supplementing the missing data by the supplementary data, and replacing the data with obvious errors.

Preferably, the unifying longitude and latitude coordinate systems of the plurality of data sources to perform space-time matching on the plurality of data sources includes:

and extracting provincial charging stations from the Chinese provincial data, checking information of the provincial charging stations by adopting the Chinese provincial data, unifying data of all data sources into a WGS-84 standard coordinate system by using a longitude and latitude coordinate conversion method or ArcGIS software, and performing space-time matching on the data of all the data sources to ensure that the multi-source data are mutually matched in time and space.

Preferably, the simplified merging processing of the national highway road GIS data includes:

the highway comprises bidirectional main lines, main grade crossing lines and ramp basic elements, all data entries belonging to the same grade crossing in the national highway GIS data are merged to obtain a merged road data set omega and a grade crossing set, the uplink and downlink data entries of the bidirectional highway in the national highway GIS data are merged, and the grade crossing in the merged road data set omega and the bidirectional highway are merged.

Preferably, the simplified merging processing is performed on the national highway GIS data to obtain a merged road data set omega and a solid intersection set, and the method includes:

in the field of 'head end point longitude and latitude (X1Y 1)' of the road GIS data, adding all non-repeated head end point longitude and latitude into a set N_h；

Set N by spatial distance_hThe middle individuals are clustered, all the individuals with the gravity center distance less than 1.5km are clustered into a subclass, and the gravity center distance D of the individual a_aThe calculation method of (2) is as follows:

wherein x is the longitude of the individual, y is the latitude of the individual, and n is the number of samples in the class;

regarding a subclass with the sample number more than or equal to 6 as a grade crossing, wherein elements of the subclass are head and tail end points of all main lines and ramps of the grade crossing, searching road GIS data entries of which all head end point longitude and latitude (X1Y1) and tail end point longitude and latitude (X2Y2) are elements in the subclass for any subclass considered as the grade crossing, merging all the road GIS data entries into one piece of data, adding the data into a new merged road data set omega, and removing the merged data entry from an original road GIS data set;

obtaining a set of solid intersections J ═ J₁,j₂,…,j_mAnd (3) calculating the coordinate position of each solid cross by using the longitude and latitude mean value of the individuals in the subclass according to a formula (2)

Namely according to the formula:

preferably, the merging the uplink and downlink data entries of the bidirectional expressway in the national expressway road GIS data includes:

step 2.1: judging whether each road in the GIS data set of the national highway roads has an opposite road or not by adopting a mode of converting line data into point data or directly processing the line data, and if one road is parallel and adjacent to the current road and the distance between the two roads is within 500 meters, determining that the opposite road exists;

step 2.2: pairing GIS data of all mutually opposite roads, and recording data items of successfully paired road data;

step 2.3: judging whether the road is complete or not for any one group of paired road 1 and road 2, representing the upstream and downstream end points of the road 1 by using a point A and a point B, representing the upstream and downstream end points of the road 2 by using a point C and a point D, and adding the road into a combined road data set L if the linear distance of the point A, D and the linear distance of the point B, C do not exceed 2 kilometers; if not, continuing to execute the following steps;

step 2.4: for the incomplete matched roads, judging whether other matched roads exist on the longer side road, and if other matched roads exist, executing the step 2.5; otherwise, adding the merged bidirectional road into the merged road data set L;

step 2.5: judging whether other paired roads and the road on the shorter side are mutually connected roads, if so, merging the other paired roads and the road on the shorter side into one road, and executing the step 2.3; if the roads are not connected, namely ramp exits or intersections exist among the roads, the longer side of the road is broken at the ramps or the intersections, the longer side of the road is respectively re-paired with other paired roads and the shorter side of the road, the longer side of the road is divided into two groups of paired roads, and the step 2.3 is respectively executed;

step 2.6: acquiring set L ═ L of bidirectional roads₁,l₂,…,l_kK is the number of bidirectional roads in the set L.

Preferably, the merging of the grade crossing in the set Ω and the bidirectional expressway road includes:

for each bidirectional road l in the merged road dataset omega_i,l_iE to L, respectively recording two end points as a and b, extracting the end points of the sub-direction roads at two sides of the bidirectional road as a₁,b₁And a₂,b₂；

Search and number a₁,a₂Directly connected solid intersections, denoted j_a,j_aE.g. J, search and number b₁,b₂Directly connected solid intersections, denoted j_b,j_b∈J；

Will make the solid cross j_aSet as a bidirectional road_iAt the end point of the a-side, i.e. a bidirectional road l is set_iThe label 'end point a' is j_aWill be three-dimensionally crossed j_bSet as a bidirectional road_iAt the end point of the b-end, i.e. a bidirectional road l is set_iThe label 'b terminal point' is j_b。

Preferably, the fusing and matching of the highway toll station GIS data, the chinese provincial junction data and the simplified and merged highway road GIS data includes:

fusing and matching the GIS data of the highway toll station, the provincial boundary data and the simplified and combined GIS data of the highway road, fusing and associating the GIS data of the toll station and the GIS data of the road, fusing and matching the ramp toll station and the grade crossing, and fusing and matching the main toll station and the bidirectional road;

the method is characterized in that a data fusion method is adopted to match the highway toll station to a corresponding three-dimensional crossing or two-way road, and the specific method is as follows:

step 1: adding all highway toll stations into a highway toll station set S, dividing the highway toll stations into two types according to a toll station type field in GIS data of the highway toll stations, wherein one type is a highway ramp toll station which is arranged on a toll station connected with a ramp of the highway, and using the set S_rIs expressed by s, its element_rIs shown, i.e.

One is highway main line toll station, which is set on highway passage and uses set S_mIs expressed by s, its element_mIs shown, i.e.

Step 2: and performing fusion matching on the ramp toll station and the grade crossing, namely performing the following operations:

step 2.1: general ramp toll station s_rIs expressed as

Ramp toll station s_rAnd a solid cross j_iExpressed as follows:

step 2.2: to any ramp toll station s_r∈S_rCalculate it to any one fly-over j_iE.g. J, and keep in charge station s_rHas a minimum Euclidean distance of

Toll station s_rHas a minimum distance of

Step 2.3: setting up toll stations s_rThe label of (A) matching the stereo cross is

If the label of the grade crossing 'matching toll station' is empty, the label is set as s_rOtherwise will s_rAdding to the end of the tag content;

and step 3: the main line toll station and the bidirectional road are fused and matched, namely the following operations are executed:

step 3.1: main line toll station s_mIs expressed as

Two-way road_iTwo end points

And b_liRespectively have a longitude and a latitude of

And

order to

d_a,bAre respectively s_mAnd

s_mand

and

the Euclidean distance of (a) is,

main line toll station s_mTo a bidirectional road_iThe distance of (d) is expressed as:

wherein

Step 3.2: for arbitrary main line toll station s_m∈S_mCalculate it to any bidirectional road l_iE.g. distance of L, and recording toll station s_mHas a minimum distance of

Toll station s_mThe distance between the two-way roads is

And recording bidirectional road and toll station s_mThe nearest position is the insertion point of the main line toll station;

step 3.3: will two-way road

Two bidirectional roads interrupted from the insertion point, and recorded as

And

setting up toll stations s_mThe label of "match bidirectional road" is

And

setting a bidirectional road

And

the label corresponding to the end point of the inserting end is a toll station s_m。

Preferably, the constructing a national highway network topology based on the multi-source data after the fusion processing includes:

the national highway topological network is represented as a fully-connected undirected graph G ═ V, A }, wherein V is a node set of the highway topological network, and A is a road section set of the highway topological network:

the national highway topological network node data set comprises a node number, a node name, a region, a node attribute, a sequence number and longitude and latitude coordinate fields, and the specific method for constructing the national highway topological network node data set is as follows:

constructing a toll station node data set, and adding the toll station type field into a set S for all toll stations of GIS data of national highway toll stations if the toll station type field is' provincial toll station_pElse add to the collection

Performing the following steps;

constructing a cross point node data set, and performing a stereo crossing j on any one of the nodes_iE.g. J, if the solid cross J_iThe label "matching toll booth" of is empty, it is added to the set V_cPerforming the following steps;

the national expressway topological network road section data set comprises road section numbers, road section starting node numbers, road section end node numbers and mileage fields, and is constructed by an improved road section deletion method, and the specific method comprises the following steps:

step 1: initializing, setting a set Q as V, setting a set A of a topological network edge as phi, taking a bidirectional road set L, and taking a node i as a first element in the set Q;

step 2: searching directly adjacent nodes of the node i through two labels of an end point a and an end point b of the bidirectional road data set L, adding the directly adjacent nodes into a set J (i), and adding a bidirectional road connecting the two directly adjacent nodes into a set A (i);

and step 3: for any A_ijE.g. A (i) and A_ijAdding the bidirectional road into a road section set A of the expressway topology network, and removing the corresponding bidirectional road from a set L;

and 4, step 4: putting Q as Q \ i;

and 5: if Q is equal to phi, ending, otherwise, making i be the first element in the set Q, and returning to the step 2;

step 6: and outputting the road section set A of the expressway network topology.

According to the technical scheme provided by the embodiment of the invention, the national expressway network topology is constructed based on a plurality of data sources such as the national expressway toll station GIS data, the national expressway road GIS data and the Chinese provincial data, the multi-source data is fully utilized, the information integrity and the structural simplicity of the expressway network topology are comprehensively considered, and the method is suitable for large-scale networks. The method constructs a network topology based on the grade separation, the toll station and the two-way road of the expressway, and has simple algorithm and easy implementation.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a processing flow chart of a national highway network topology construction method based on multi-source data according to an embodiment of the present invention;

fig. 2 is a flowchart of a method for merging an uplink road and a downlink road of a bidirectional highway according to an embodiment of the present invention;

fig. 3 is a flowchart for constructing a topological road segment for an expressway with improved road segment deletion according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of highway line data according to an embodiment of the present invention;

fig. 5 is a partially enlarged schematic view of a data schematic diagram of an expressway road line according to an embodiment of the present invention;

fig. 6 is a schematic diagram illustrating fusion and matching between a ramp toll station and a grade separation provided in an embodiment of the present invention;

fig. 7 is a schematic diagram illustrating a fusion matching between a main line toll station and a bidirectional road according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

For the convenience of understanding the embodiments of the present invention, the following description will be further explained by taking several specific embodiments as examples in conjunction with the drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.

Example one

The embodiment of the invention provides a nationwide expressway network topology construction method based on multi-source data, aiming at the problems of difficulty in obtaining source data, different normalization of the multi-source data, low efficiency of processing and analyzing algorithms and the like in the construction of large-scale network topology, and comprehensively considering the information integrity and the structural simplicity of the expressway network topology. The processing flow of the method is shown in fig. 1, and comprises the following processing steps:

step S10: firstly, multi-source data required by constructing national highway network topology are collected, and the multi-source data are preprocessed according to the characteristics of completeness, accuracy, normalization and the like of the data.

Collecting multi-source data required for constructing national highway network topology, such as national highway toll station GIS (Geographic Information System) data, national highway road GIS data and national provincial data, wherein:

the national highway toll station GIS data is point data, and includes main field information such as toll station number, toll station serial number, toll station name abbreviation, province of the toll station, toll station type, and toll station longitude and latitude, and the field meaning and example of the toll station GIS data are as shown in table 1:

table 1: meaning and example of fields for toll station GIS data

The national highway GIS data is line data including main field information such as a road number, a road name, a road length, a city code, a head end point number, a tail end point number, head end point longitude and latitude, and tail end point longitude and latitude, and the field meaning and example of the road GIS data are as shown in table 2:

table 2: field meaning and examples for road GIS data

The chinese provincial data is dot data, which includes main field information such as provincial point number, province number, longitude and latitude, and the field meaning and example of the provincial data are as follows:

table 3: field meaning and examples of provincial data

Step S20: missing data leakage and erroneous data replacement.

The method comprises the steps of directly obtaining information loss or errors of highway GIS data or provincial data, identifying positions where the loss and error data exist, judging feature information of the loss data and the error data, crawling supplementary data from an online map by Python software according to the feature information, supplementing the loss data by the supplementary data, and replacing the data with obvious errors.

Step S30: and unifying longitude and latitude coordinate systems of the plurality of data sources. The national highway toll station GIS data, the road GIS data, the Chinese provincial data and the crawled supplementary data all contain longitude and latitude position information. Due to the difference of the acquisition way, the accuracy and the normalization of the data, a plurality of longitude and latitude coordinate systems which represent the position information exist in the multi-source data, such as a WGS-84 standard coordinate system, a national bureau of surveying GCJ-02 coordinate system, a Baidu BD-09 coordinate system and the like. And unifying all data into a WGS-84 standard coordinate system by using a longitude and latitude coordinate conversion method or ArcGIS software.

Step S40: and (4) performing space-time matching on the multi-source data. Over time, roads and toll booths on highways may change due to reconstruction, removal, or migration, resulting in differences in highway data collected at different times. Therefore, it is necessary to ensure that the multi-source data are collected in the same time and space, and the multi-source data are matched with each other in time and space.

Step S50: and extracting the provincial charging station. And extracting all provincial charging stations, and checking the information of the provincial charging stations by adopting Chinese provincial data.

Step S60: and simplifying and combining the GIS data of national highway roads. Since the highway road comprises basic elements such as main lines (bidirectional), stereo crossing main lines and ramp, each element is stored in the GIS data of the highway road as an independent data entry, but the topological relation of the highway network is difficult to be directly judged according to the GIS data. In order to accurately identify nodes and road sections of a network topology from mass data, the national highway network needs to be abstracted and simplified, that is, before the national highway network topology is constructed, road GIS data is simplified and merged, and fig. 2 is a flow chart of an uplink and downlink road method for merging bidirectional highways provided by the embodiment of the invention. The specific method for simplifying the merging process is as follows:

step 1: merging all data entries belonging to the same grade crossing in the road GIS data, namely executing the following operations:

step 1.1: in the field of 'head end point longitude and latitude (X1Y 1)' of the road GIS data, adding all non-repeated head end point longitude and latitude into a set N_h。

Step 1.2: set N by spatial distance_hAnd (3) clustering the medium individuals, and clustering all individuals with the gravity center distance less than 1.5km into a subclass, wherein the gravity center distance calculation method of the individual a is as follows:

where x is the longitude of the individual, y is the latitude of the individual, and n is the number of samples in the class.

Step 1.3: and regarding a subclass with the sample number being greater than or equal to 6 as a stereo cross, wherein the elements of the subclass are the head and tail end points of all positive lines and ramps of the stereo cross.

Step 1.4: for any subclass regarded as the grade crossing, searching all road GIS data entries of which the head end point longitude and latitude (X1Y1) and the tail end point longitude and latitude (X2Y2) are elements in the subclass, merging the road GIS data entries into a piece of data, adding the data into a new merged road data set omega, and removing the merged data entries from the original road GIS data set.

Step 1.5: obtaining a set J ═ tone of solid intersectionj₁,j₂,…,j_mAnd m is the number of the stereo crossovers in the set. Calculating the coordinate position of each solid intersection by using the longitude and latitude mean value of the individuals in the subclass

Namely according to the formula:

step 2: merging uplink and downlink data items of a bidirectional expressway in road GIS data, namely executing the following operations:

step 2.1: and judging whether each road in the road GIS data set has an opposite road or not by adopting a mode of converting line data into point data or directly processing the line data. If one road is parallel and adjacent to the current road, the distance between the two roads is within 500 meters, and the opposite road is considered to exist.

Step 2.2: and all GIS data of the opposite roads are paired, and data items of each road data successfully paired are recorded.

Step 2.3: for any set of paired road 1 and road 2, it is determined whether the road is complete. Points A and B are used for representing the upstream and downstream end points of the road 1, points C and D are used for representing the upstream and downstream end points of the road 2, if the linear distance between the point A, D and the point B, C does not exceed 2 kilometers, the road is considered to be complete, and the road is added into a combined road data set L; otherwise, the step is regarded as incomplete, and the following steps are continuously executed.

Step 2.4: and judging whether other matched roads (marked as road 3) exist on the longer road (marked as road 1) for the incomplete matched road. If the road 3 exists, executing the step 2.5; otherwise, the merged bidirectional road is added to the merged road data set L.

Step 2.5: judging whether the road 3 and the road (marked as the road 2) on the shorter side are mutually connected, if so, merging the road 2 and the road 3 into one road, and executing the step 2.3; if the roads are not connected, namely ramp exits or intersections exist among the roads, the road 1 is broken at the ramps or the intersections, and is respectively re-paired with the roads 2 and 3, the roads are divided into two groups of paired roads, and the step 2.3 is respectively executed.

Step 2.6: acquiring set L ═ L of bidirectional roads₁,l₂,…,l_kK is the number of bidirectional roads in the set L.

And step 3: merging the grade crossing in the set omega with the bidirectional expressway road, namely, performing the following operations:

step 3.1: for each bidirectional road l in the set Ω_i,l_ie.L, respectively recording two end points as a and b, extracting end points of the direction-dividing roads (namely the road 1 and the road 2) at two sides of the bidirectional road, and respectively recording the end points as a₁,b₁And a₂,b₂。

Step 3.2: search and number a₁,a₂Directly connected solid intersections, denoted j_a,j_aE.g. J, search and number b₁,b₂Directly connected solid intersections, denoted j_b,j_b∈J。

Step 3.3: will make the solid cross j_aSet as a bidirectional road_iAt the end point of the a-side, i.e. a bidirectional road l is set_iThe label 'end point a' is j_a. Will make the solid cross j_bSet as a bidirectional road_iAt the end point of the b-end, i.e. a bidirectional road l is set_iThe label 'b terminal point' is j_b。

And fusing and matching the multi-source data such as the GIS data of the highway toll station, the provincial boundary data, the simplified and combined GIS data of the highway road and the like. Because the multi-source data are mutually independent, each data is stored in the data file as independent information, and therefore, the association relationship among the multi-source data is difficult to directly construct. In order to accurately acquire nodes of a highway network topology from the GIS data of a toll station, accurately acquire connection sections between the nodes from the GIS data of a road, and acquire provincial/non-provincial attributes of the nodes from the provincial data, fusion matching of multi-source data is required. The fusion matching of the multi-source data is mainly to perform fusion association on the toll station GIS data and the road GIS data, and comprises fusion matching of a ramp toll station and a grade crossing and fusion matching of a main line toll station and a bidirectional road. The specific method for matching the highway toll station to the corresponding grade crossing or bidirectional road by adopting the data fusion method is as follows:

step 1: all highway tollgates are added to the highway tollgate set S. The expressway toll stations are divided into two types according to a toll station type field in GIS data of the expressway toll station, one type is an expressway ramp toll station, the ramp toll station is a toll station arranged on a ramp connected with the expressway, and a set S is used_rIs expressed by s, its element_rIs shown, i.e.

One is highway main line toll station, which is toll station set on highway passage way and uses set S_mIs expressed by s, its element_mIs shown, i.e.

Step 2: and performing fusion matching on the ramp toll station and the grade crossing, namely performing the following operations:

step 2.1: general ramp toll station s_rIs expressed as

Ramp toll station s_rAnd a solid cross j_iExpressed as follows:

step 2.2: for any rampToll station s_r∈S_rCalculate it to any one fly-over j_iE.g. J, and keep in charge station s_rHas a minimum Euclidean distance of

Toll station s_rHas a minimum distance of

Step 2.3: setting up toll stations s_rThe label of (A) matching the stereo cross is

If the label of the grade crossing 'matching toll station' is empty, the label is set as s_rOtherwise will s_rAdded to the end of the tag content.

And step 3: the main line toll station and the bidirectional road are fused and matched, namely the following operations are executed:

step 3.1: main line toll station s_mIs expressed as

Two-way road_iTwo end points

And

respectively have a longitude and a latitude of

And

order to

d_a,bAre respectively s_mAnd

s_mand

and

the Euclidean distance of (a) is,

main line toll station s_mTo a bidirectional road_iThe distance of (d) is expressed as:

wherein

Step 3.2: for arbitrary main line toll station s_m∈S_mCalculate it to any bidirectional road l_iE.g. distance of L, and recording toll station s_mHas a minimum distance of

Toll station s_mThe distance between the two-way roads is

And recording bidirectional road and toll station s_mThe nearest location is the main line toll station insertion point.

Step 3.3: will two-way road

Two bi-directional break from insertion pointRoad, mark as

And

setting up toll stations s_mThe label of "match bidirectional road" is

And

setting a bidirectional road

And

the label corresponding to the end point of the inserting end is a toll station s_m。

Step S70: and constructing a national highway network topology by adopting the multi-source data subjected to fusion processing.

The national highway topological network is represented as a fully-connected undirected graph G ═ V, A }, wherein V is a node set of the highway topological network, and A is a road section set of the highway topological network. The national highway topology network comprises the following basic elements:

(1) node point

In a national highway topology network, nodes can be divided into two categories, one is a highway intersection set, and V is used_cIs represented by v, the elements of which are_cIs shown, i.e.

The highway intersections are points where different highways or highways and ordinary roads are connected and converted by a solid intersection; the other is a set of highway toll stations, denoted by S, which are nodes with toll collection functions. The highway toll stations are divided into two types according to different toll attributes, wherein one type is a highwayHighway provincial toll station set using S_pIs expressed by s, its element_pIs shown, i.e.

The provincial toll station only has a toll collection function, and vehicles cannot drive into or out of the highway; the other is a highway non-provincial toll station set

Is expressed by elements of

Is shown, i.e.

The non-provincial toll station has functions of charging and vehicle entering and exiting.

The national highway topology network node data set comprises fields such as node numbers, node names, regions, node attributes, sequence numbers, longitude and latitude coordinates and the like. The specific method for constructing the national highway topological network node data set is as follows:

construct the toll gate node data set. For all toll stations of GIS data of national highway toll Station, if the field of ' toll Station Type ' (Station Type) ' is ' provincial toll Station ', it is added to the set S_pElse add to the collection

In (1).

Construct a cross-point node dataset. For any one of the stereo intersections j_iE.g. J, if the solid cross J_iThe label "matching toll booth" of is empty, it is added to the set V_cIn (1).

(2) Road section

In a national highway topology network, a segment represents a highway road connection between adjacent toll booths or intersections, denoted by a, a ∈ a. In order to construct a section of the highway topology network, the definition of the directly adjacent nodes is given, namely two highway topology nodes which are only directly connected by a highway road closed in two directions and do not pass through any grade crossing or an entrance ramp are called directly adjacent nodes. And the road between the directly adjacent nodes is the road section of the topological network.

Fig. 3 is a flowchart for constructing a topological road segment for an expressway through improved road segment deletion according to an embodiment of the present invention. The national highway topological network road section data set comprises fields such as road section numbers, road section starting node numbers, road section terminal node numbers, mileage and the like. The invention provides an improved road segment deletion method for constructing a topological network road segment data set of a national expressway, which comprises the following specific steps:

step 1: initializing, setting a set Q as V, setting a set A of a topological network edge as phi, taking a bidirectional road set L, and taking a node i as a first element in the set Q;

step 2: searching directly adjacent nodes of the node i through two labels of an end point a and an end point b of the bidirectional road data set L, adding the directly adjacent nodes into a set J (i), and adding a bidirectional road connecting the two directly adjacent nodes into a set A (i);

and step 3: for any A_ijE.g. A (i) and A_ijAdding the bidirectional road into a road section set A of the expressway topology network, and removing the corresponding bidirectional road from a set L;

and 4, step 4: putting Q as Q \ i;

and 5: if Q is equal to phi, ending, otherwise, making i be the first element in the set Q, and returning to the step 2;

step 6: and outputting the road section set A of the expressway network topology.

Example two

The method comprises the steps of firstly, collecting multi-source data such as national highway toll station GIS data, national highway GIS data and national provincial data, preprocessing the national highway GIS data based on common data processing methods such as data leakage filling, longitude and latitude conversion, space-time matching and data association, and ensuring the integrity and effectiveness of the multi-source data. Secondly, according to the characteristics of the highway GIS data, the information integrity and the structural simplicity of the highway network topology are comprehensively considered, and a simplified merging method of the highway GIS data is provided. The basic idea of simplified merging is: merging the GIS data of the roads belonging to the same grade crossing; merging the uplink and downlink sections of the bidirectional road; the grade crossing is merged with the bidirectional road data. The merged data can be used for fusion processing with other multi-source data and extraction of basic elements of highway topology. Moreover, carry out multisource data fusion and match, the core of fusion and match is the fusion and match of toll station GIS data and road GIS data, specifically includes: the ramp toll station is matched with the stereo crossing in a fusion way, and the main line toll station is matched with the bidirectional road in a fusion way. Finally, constructing a node set of the highway topology network according to the toll station data set and the stereo crossing set; and constructing a road section set of the highway topological network by adopting an improved road section deletion method.

Here, the method for simplifying and merging the national highway GIS data according to the embodiment of the present invention will be described with reference to a part of the highway GIS data. The road GIS data samples thus preprocessed are shown in table 4, and the line data corresponding to the sample data are shown in fig. 4 and 5. Wherein fig. 5 is a partial enlarged view of the circled position in fig. 4. The numbers in fig. 4 and 5 correspond to the head and end point numbers of the road data, i.e., the fields "FJCID" and "TJCID". For example, the road data in which "Link ID" is 1, the head point number is 1, and the end point number is 3; the "Link ID" is road data of 4, the head point number is 3, and the end point number is 8.

Table 4: highway road GIS data sample

(1) And merging the road GIS data belonging to the same grade crossing. Clustering all 'road section head and end points' according to spatial distanceIn the example data shown, the head ends or end points of the roads numbered 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 are grouped into one type (the end point of a road is also the head end point of the road following the road), and are regarded as one solid intersection and are denoted by j₁. For this one fly-over subclass, the roads in which the "head end point number" and the "end point number" are both in this subclass are searched for, and their "Link IDs" are 3, 4, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24 and 25, respectively, these road data are merged into one fly-over, and the fly-over coordinate position is calculated from the latitude and longitude of each individual in the subclass by the following formula:

(2) and merging the uplink and downlink road sections belonging to the same two-way road. Two road data entries having "Link ID" of 1 and 9 are mutually opposite roads, merged into a bidirectional road, and denoted as l₁. Through inspection, the bidirectional road₁Is complete and can be added directly to the merged road set. Similarly, the road data with "Link ID" of 26 and 28 can be merged into a bidirectional road, denoted as l₂(ii) a Merging the road data with "Link ID" of 2 and 5 into a bidirectional road, which is marked as l₃(ii) a Merging the road data with "Link ID" of 18 and 27 into a bidirectional road, denoted as l₄。

(3) And merging the adjacent grade crossings and the bidirectional roads. Two-way road₁The end points on the southeast side of the road intersect with the solid intersection j through the end points with the numbers of the head points or the end points being 3 and 7₁Directly connected and provided with a bidirectional road l₁The end point at the corresponding end is j₁. In the same way, the bidirectional road l₂The end points on the southwest side intersect with the solid intersection j by the head and end points numbered 15 and 18₁Direct phaseConnecting; two-way road₃The end points on the northeast side intersect with the solid j by the head and tail end points numbered 4 and 6₁Directly connecting; two-way road₄The end points on the northwest are intersected by the first and last end points numbered 13 and 17 with the solid intersection j₁Are directly connected. Therefore, the bidirectional roads l are respectively set₂,l₃And l₄The end point label at the corresponding end is j₁。

The merged road GIS data are stored in the set omega. The elements in the set omega are divided into two types, one type is a stereo cross set and is marked as J ═ J₁,j₂,…,j_m}; the other is a bidirectional road set, which is marked as L ═ L₁,l₂,…,l_k}. And respectively fusing and matching the grade separation set and the bidirectional road set in the set omega with a ramp toll station and a main line toll station.

(1) And the ramp toll station is fused and matched with the stereo cross.

Two ramp toll stations s₁,s₂Is intersected with a horn-shaped solid_sA schematic of fusion matching is shown in fig. 6. According to the calculated three-dimensional intersection coordinate position and the 'toll station longitude and latitude' field information of the ramp toll station when the road data are combined, the Euclidean distance between any one ramp toll station and all three-dimensional intersections can be calculated. Solid cross j in fig. 6_sIs ramp toll station s₁And s₂The Euclidean distance of (1) is the minimum stereo crossing, namely the following two formulas are simultaneously satisfied:

so that the ramp toll station s can be used₁,s₂Is intersected with the solid j_sFusion matching, i.e. setting toll stations s₁And s₂The label of is_sA toll station s₁And s₂Added to the fly-over j_sThe label "match toll station" end.

(2) And the main line toll station is fused and matched with the bidirectional road.

One main line toll station s_mAnd two-way road

A schematic of fusion matching is shown in fig. 7. The Euclidean distance from any one main line toll station to all bidirectional roads can be calculated by using the 'toll station longitude and latitude' of the main line toll station and the longitude and latitude information of two end points of the bidirectional roads. Bidirectional road in fig. 7

Is the main line toll station s_mThe two-way road with the minimum Euclidean distance meets the following conditions:

thus, the main line toll station s can be used_mAnd two-way road

And fusing and matching. Will two-way road

From main toll station s_mThe insertion point is broken and split into two bidirectional roads of

And

setting up toll stations s_mThe label of "match bidirectional road" is

And

setting a bidirectional road

And

the label corresponding to the end point of the inserting end is a toll station s_m. At this time, the two-way road

And

the other ends of which are respectively and directly connected with two solid crossings in the figure.

And finally, constructing a national highway network topology according to the GIS data obtained by merging, processing and fusion matching, wherein the highway network topology comprises two basic elements of nodes and road sections.

(1) Highway network topology node.

Nodes of the highway network topology include intersections and highway tolls. The toll stations are divided into provincial toll stations and non-provincial toll stations and are acquired from GIS data of the toll stations; the cross points are points converted by solid cross connection between different expressways or expressways and common roads, and a cross point set V of the network topology nodes of the expressways_cAnd the system consists of a stereo cross with a label of a matching toll station in the set J being empty.

A sample of a portion of the highway network topology nodes is shown in table 5.

Table 5: highway topology network node data sample

(2) And (4) topological sections of the expressway network.

The segments of the highway network topology are bidirectional roads connecting directly adjacent nodes. In the L in the bidirectional road set, an end point of any one bidirectional road is connected to a node of a topology network such as a flyover (divided into an intersection and a ramp toll station according to a fusion situation) or a main line toll station. Therefore, the bidirectional road is a highway network topology section connecting nodes at two ends of the bidirectional road.

In order to avoid duplication or omission in the process of identifying the topological network sections, the invention adopts an improved section deletion method to construct the section set of the expressway topological network, and the examples of partial expressway network topological sections are shown in table 6.

Table 6: highway topology network side data sample

In summary, the national highway network topology is constructed based on a plurality of data sources such as national highway toll station GIS data, national highway GIS data and Chinese provincial data, multi-source data are fully utilized, and information integrity and structural simplicity of the highway network topology are comprehensively considered.

The method for constructing the expressway network topology of the embodiment of the invention is based on the national expressway network to construct the topology model, and is suitable for large-scale networks. The method takes longitude and latitude information as a main factor and information such as province, name, number and the like as a secondary factor to carry out multi-source data association fusion, and makes full use of the multi-source data information; the method constructs a network topology based on the grade separation, the toll station and the two-way road of the expressway, and has simple algorithm and easy implementation.

The construction method of the expressway network topology provided by the embodiment of the invention solves the basic conditions of the problems of provincial expense clearing, traffic path identification and the like based on a theoretical method, is suitable for solving the problems related to expressway flow distribution, and provides a basis for solving the provincial clearing problem of the expressway.

Those of ordinary skill in the art will understand that: the figures are merely schematic representations of one embodiment, and the blocks or flow diagrams in the figures are not necessarily required to practice the present invention.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A national highway network topology construction method based on multi-source data is characterized by comprising the following steps:

collecting multi-source data required for constructing national highway network topology, wherein the multi-source data comprises national highway toll station GIS data, national highway road GIS data and national provincial data;

unifying longitude and latitude coordinate systems of a plurality of data sources, and performing space-time matching on the plurality of data sources;

simplifying and combining the GIS data of national highway roads;

and performing fusion matching on the GIS data of the highway toll station, the China provincial data and the simplified and combined GIS data of the highway road, and constructing a national highway network topology based on the fused multi-source data.

2. The method of claim 1, wherein the national highway toll station GIS data is point data comprising toll station number, toll station serial number, toll station name abbreviation, province of the toll station, toll station type, and toll station longitude and latitude field information; the national highway GIS data is line data which comprises road numbers, road names, road lengths, city codes, head end point numbers, tail end point numbers, head end point longitudes and latitudes and field information of tail end point longitudes and latitudes; the Chinese provincial data is point data and comprises provincial point numbers, provinces, province numbers, longitude and latitude fields.

3. The method of claim 1, further comprising: identifying the positions of missing data and error data in the multi-source data, judging the feature information of the missing data and the error data, crawling supplementary data from an online map by Python software according to the feature information, supplementing the missing data by the supplementary data, and replacing the data with obvious errors.

4. The method of claim 1, wherein unifying the longitude and latitude coordinate systems of the plurality of data sources to perform spatio-temporal matching on the plurality of data sources comprises:

and extracting provincial charging stations from the Chinese provincial data, checking information of the provincial charging stations by adopting the Chinese provincial data, unifying data of all data sources into a WGS-84 standard coordinate system by using a longitude and latitude coordinate conversion method or ArcGIS software, and performing space-time matching on the data of all the data sources to ensure that the multi-source data are mutually matched in time and space.

5. The method according to any one of claims 1 to 4, wherein the simplified merging process of the national highway road GIS data comprises:

the highway comprises bidirectional main lines, main grade crossing lines and ramp basic elements, all data entries belonging to the same grade crossing in the national highway GIS data are merged to obtain a merged road data set omega and a grade crossing set, the uplink and downlink data entries of the bidirectional highway in the national highway GIS data are merged, and the grade crossing in the merged road data set omega and the bidirectional highway are merged.

6. The method of claim 5, wherein the simplified merging of the national highway GIS data to obtain the merged road data set Ω and the solid intersection set comprises:

in the field of 'head end point longitude and latitude (X1Y 1)' of the road GIS data, adding all non-repeated head end point longitude and latitude into a set N_h；

Set N by spatial distance_hThe middle individuals are clustered, all the individuals with the gravity center distance less than 1.5km are clustered into a subclass, and the gravity center distance D of the individual a_aThe calculation method of (2) is as follows:

wherein x is the longitude of the individual, y is the latitude of the individual, and n is the number of samples in the class;

regarding a subclass with the sample number more than or equal to 6 as a grade crossing, wherein elements of the subclass are head and tail end points of all main lines and ramps of the grade crossing, searching road GIS data entries of which all head end point longitude and latitude (X1Y1) and tail end point longitude and latitude (X2Y2) are elements in the subclass for any subclass considered as the grade crossing, merging all the road GIS data entries into one piece of data, adding the data into a new merged road data set omega, and removing the merged data entry from an original road GIS data set;

obtaining a set of solid intersections J ═ J₁,j₂,…,j_mAnd (3) calculating the coordinate position { x) of each solid cross by using the longitude and latitude mean value of the individuals in the subclass according to a formula (2), wherein m is the number of the solid cross in the set_ji,y_jiI.e. according to the formula:

7. the method of claim 5, wherein merging the upstream and downstream data entries for the bidirectional highways in the national highway GIS data comprises:

step 2.1: judging whether each road in the GIS data set of the national highway roads has an opposite road or not by adopting a mode of converting line data into point data or directly processing the line data, and if one road is parallel and adjacent to the current road and the distance between the two roads is within 500 meters, determining that the opposite road exists;

step 2.2: pairing GIS data of all mutually opposite roads, and recording data items of successfully paired road data;

step 2.3: judging whether the road is complete or not for any one group of paired road 1 and road 2, representing the upstream and downstream end points of the road 1 by using a point A and a point B, representing the upstream and downstream end points of the road 2 by using a point C and a point D, and adding the road into a combined road data set L if the linear distance of the point A, D and the linear distance of the point B, C do not exceed 2 kilometers; if not, continuing to execute the following steps;

step 2.4: for the incomplete matched roads, judging whether other matched roads exist on the longer side road, and if other matched roads exist, executing the step 2.5; otherwise, adding the merged bidirectional road into the merged road data set L;

step 2.5: judging whether other paired roads and the road on the shorter side are mutually connected roads, if so, merging the other paired roads and the road on the shorter side into one road, and executing the step 2.3; if the roads are not connected, namely ramp exits or intersections exist among the roads, the longer side of the road is broken at the ramps or the intersections, the longer side of the road is respectively re-paired with other paired roads and the shorter side of the road, the longer side of the road is divided into two groups of paired roads, and the step 2.3 is respectively executed;

step 2.6: acquiring set L ═ L of bidirectional roads₁,l₂,…,l_kK is the number of bidirectional roads in the set L.

8. The method of claim 5, wherein merging the grade crossings in the set Ω with the bidirectional highway roads comprises:

for each bidirectional road l in the merged road dataset omega_i,l_iE to L, respectively recording two end points as a and b, extracting the end points of the sub-direction roads at two sides of the bidirectional road as a₁,b₁And a₂,b₂；

Search and number a₁,a₂Directly connected solid intersections, denoted j_a,j_aE.g. J, search and number b₁,b₂Directly connected solid intersections, denoted j_b,j_b∈J；

Will make the solid cross j_aSet as a bidirectional road_iAt the end point of the a-side, i.e. a bidirectional road l is set_iThe label 'end point a' is j_aWill be three-dimensionally crossed j_bSet as a bidirectional road_iAt the end point of the b-end, i.e. a bidirectional road l is set_iThe label 'b terminal point' is j_b。

9. The method according to claim 8, wherein said performing fusion matching on said highway toll station GIS data, said China provincial junction data and said simplified merged highway road GIS data comprises:

fusing and matching the GIS data of the highway toll station, the provincial boundary data and the simplified and combined GIS data of the highway road, fusing and associating the GIS data of the toll station and the GIS data of the road, fusing and matching the ramp toll station and the grade crossing, and fusing and matching the main toll station and the bidirectional road;

the method is characterized in that a data fusion method is adopted to match the highway toll station to a corresponding three-dimensional crossing or two-way road, and the specific method is as follows:

step 1: adding all highway toll stations into a highway toll station set S, dividing the highway toll stations into two types according to a toll station type field in GIS data of the highway toll stations, wherein one type is a highway ramp toll station which is arranged on a toll station connected with a ramp of the highway, and using the set S_rIs expressed by s, its element_rIs shown, i.e.

One is highway main line toll station, which is set on highway passage and uses set S_mIs expressed by s, its element_mIs shown, i.e.

Step 2: and performing fusion matching on the ramp toll station and the grade crossing, namely performing the following operations:

step 2.1: general ramp toll station s_rIs expressed as

Ramp toll station s_rAnd a solid cross j_iExpressed as follows:

step 2.2: to any ramp toll station s_r∈S_rCalculate it to any one fly-over j_iE.g. J, and keep in charge station s_rHas a minimum Euclidean distance of

Toll station s_rHas a minimum distance of

Step 2.3: setting up toll stations s_rThe label of (A) matching the stereo cross is

If the label of the grade crossing 'matching toll station' is empty, the label is set as s_rOtherwise will s_rAdding to the end of the tag content;

and step 3: the main line toll station and the bidirectional road are fused and matched, namely the following operations are executed:

step 3.1: main line toll station s_mIs expressed as

Two-way road_iTwo end points

And

respectively have a longitude and a latitude of

And

order to

d_a,bAre respectively s_mAnd

s_mand

and

the Euclidean distance of (a) is,

main line toll station s_mTo a bidirectional road_iThe distance of (d) is expressed as:

wherein

Step 3.2: for arbitrary main line toll station s_m∈S_mCalculate it to any bidirectional road l_iE.g. distance of L, and recording toll station s_mHas a minimum distance of

Toll station s_mThe distance between the two-way roads is

And recording bidirectional road and toll station s_mThe nearest position is the insertion point of the main line toll station;

step 3.3: will two-way road

Two bidirectional roads interrupted from the insertion point, and recorded as

And

setting up toll stations s_mThe label of "match bidirectional road" is

And

setting a bidirectional road

And

the label corresponding to the end point of the inserting end is a toll station s_m。

10. The method of claim 9, wherein constructing a national highway network topology based on the fused multi-source data comprises:

the national highway topological network is represented as a fully-connected undirected graph G ═ V, A }, wherein V is a node set of the highway topological network, and A is a road section set of the highway topological network:

the national highway topological network node data set comprises a node number, a node name, a region, a node attribute, a sequence number and longitude and latitude coordinate fields, and the specific method for constructing the national highway topological network node data set is as follows:

constructing a toll station node data set, and adding the toll station type field into a set S for all toll stations of GIS data of national highway toll stations if the toll station type field is' provincial toll station_pOtherwise, add to set S_pPerforming the following steps;

constructing a cross point node data set, and performing a stereo crossing j on any one of the nodes_iE.g. J, if the solid cross J_iThe label "matching toll booth" of is empty, it is added to the set V_cPerforming the following steps;

the national expressway topological network road section data set comprises road section numbers, road section starting node numbers, road section end node numbers and mileage fields, and is constructed by an improved road section deletion method, and the specific method comprises the following steps:

step 1: initializing, setting a set Q as V, setting a set A of a topological network edge as phi, taking a bidirectional road set L, and taking a node i as a first element in the set Q;

step 2: searching directly adjacent nodes of the node i through two labels of an end point a and an end point b of the bidirectional road data set L, adding the directly adjacent nodes into a set J (i), and adding a bidirectional road connecting the two directly adjacent nodes into a set A (i);

and step 3: for any A_ijE.g. A (i) and A_ijAdding the bidirectional road into a road section set A of the expressway topology network, and removing the corresponding bidirectional road from a set L;

and 4, step 4: putting Q as Q \ i;

and 5: if Q is equal to phi, ending, otherwise, making i be the first element in the set Q, and returning to the step 2;

step 6: and outputting the road section set A of the expressway network topology.

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