Nodes Lecture Note

INSTITUTE OF TECHNOLOGY DEPARTMENT: URBAN AND REGIONAL PLANNING
COURSE TITLE DESIGN OF URBAN AND REGIONAL NODES
Birhanu U. (MSc)
Urban & Regional Nodes
Definitions:
Definition-1:
Node is a point at which two lines or systems meet each other.
Example: Roads , Rail lines and Metro, etc.
Definition-2:
Node is a strategic focus into which the observer can enter, typically either
junction of paths or concentration of some characteristics.
Urban & Regional
Nodes
• Strategic for
• Transport services, public meetings and stays The strategic focus into which the observer can enter is
_____.
• Concentration of people, activities, etc. A.

B.
C.
Path
Transport service
Node
• This definition refers to urban or rural centers.

D. Land mark
Answer: C
Definition cont’d
Definition-3:
Node is a point, the strategic spot in a city/ region/ country into which an
observer can access.
Examples: -
• Active Localities
• A City
• Region (active in certain activity)
• Country(that gives specific interests
Definition-4:
It is the intensive focus to and from which one can travel.
• Places of a break in transportation Which one of the following is NOT true about urban Node?
A. places of a break in transportation
• A convergence of paths/ routes B.
C.
The Divergence of Path/route in urban system
A moments of shift from one structure to another
D. The convergence of path/routes
• Moments of shift from one structure to another Answer: B
Concepts of Nodes
• It is related to the concept of paths, events, upon journeys (land, air and sea
journeys).
• It is also related to the concept of districts/ regions/ quarters, as the cores are
the intensive foci of districts, polarizing centers.
• In all events, nodes are dominant features in urban developments.
• Although conceptually nodes are small points in a city image, they can be large
public squares or some what extended linear shapes, or even entire central
districts.
Characters of nodes
• Nodes may be simple public or activity concentration point.
• Nodes gain importance due to condensation of some uses or physical characters.
Example: - street corners, hangout or enclosed squares.
• Many nodes partake of the nature in both the junctions and concentration of
activities.
• Naming of spaces as node depend on the scale of observation.
• Nodes may be called cores (centers).

Basic Types of nodes:
Nodes can be classified into four basic types depending on their basic
nature/ character: -
• Regional nodes: - cities, towns, industrial centers, educational services, etc.
• Urban nodes: - Traffic, commercial, social service centers, public centers,

district centers, combined areas.
• Rural nodes: - Service centers, production areas, markets, etc.
• Specific area nodes: - Junctions of paths, shopping centers, service centers,

public corners etc. The location of such nodes can be in rural or urban areas.
Eifel, Paris Saint Basil Cathedral, Moscow

Statue of Liberty, NY The Eifel Tower
Sydney Opera House, Sydney Christ the Redeemer, Rio The Pyramids Giza, Cairo Leaning Tower of Pisa, Florence
Components and elements of urban nodes
1, Components and qualities
• Each node should contain distinct character.
• They have to bring required image.
• In general, they can be classified into two as to their basic character:
• Introvert (reserved) or
• Extrovert (open for all),
and also nodes have to have a character of hierarchy and size variation.
2, Defining components
• Streets, buildings, plazas, canals, landmarks, statues, seats, pavements, water
features, plants, etc.
Which one of the following is Not an elements of Urban Nodes
A. Buildings
B. Landmarks
C. Plazas
D. Facades
Answer: D
Character of Urban Nodes in Relation to other Land Forms
Classification of down town spaces/ criteria

• Size: spatial coverage.
• Use: different functions included.
• Relationships: its relation/ link to other such areas/ centers.
• Style: beauty/ aesthetics of the area.
• Predominant function: most important/ largest function.
• Forms: Character .
• Location: position in relation to other parts.
• Hierarchy: level of importance for the city and region.
Character of Urban Nodes in Relation to other Land Forms cont…
• Paths/roads/ streets: channels of observers where

public concentration and activities develop.
• Edges: ends of lines, ends of walls, shores, etc. They

are means of organizing spaces and attracting
activities.
A point of reference external to the

Districts: Medium large area, spaces to be entered observer and attracting activities around
them is referred to as _________.
A. District
widely, dominant with elements. B. Landmark
C. Nodes
D. Edges
Answer: B
Land marks: Points of references, external/ not

accessed but attracting activities around them.
These elements are developed with overlap or
sides by side.
Street Plaza: small portion of public open spaces immediately adjacent to side
walkways.
Corporate Foyers: Part of a new generally high rise building complexes.

The Urban Oasis: More heavily planted and has garden park image, partially
secluded from street.
Transit Foyers: a type of plaza space created at heavily used public transit
terminals (subway, bus terminals)
Differences of nodes and land marks
• Land marks are other types of points of references.
• Mostly land mark is a simple physical object like buildings, statue, hill,
mountain, etc.
• Some land marks are accessible places like elevated public spaces, but
visible and reference for orientation.
• Some land marks are distant objects being seen from different directions/
angles.
Differences of nodes and land marks cont…
• Land mark is a prime aid of orientation as the prominent land marks are tall
verticals.
• Nodes are accessed by observers.
• Nodes are places where break in transport and decisions are made to
take direction, changing mode, etc.
Examples of land marks:

• Distant view of municipality, Lagare, Entoto, Nekemte mazoria 1, Nekemte city hall
etc.
Urban and regional Nodes: Squares
Definition:
• Square can be identified as a space enclosed/ defined by building blocks,
trees, pavement or a block of buildings surrounded by streets. There are
two basic types of squares, public and traffic squares.
• Public square is an open, usually four-sided area in a city or town where

two or more streets meet, often containing trees, grass, and benches for
recreational purposes.
• Traffic square: is a road or railway junction at which two or more lines

meet each other. It is commonly dominated by motorized traffic.
Urban and regional Nodes: squares
The public and traffic squares are known as two basic types of squares.
Urban public Squares: Traffic square:
• Places of statue and fountain • Means of joining streets/ roads
• Open space for games
• Facilitation for smooth traffic flow
• Open space in a city
• Four sided open area for recreation • Traffic circle/ round about/ junction
Abba Geda, Adama Freedom square fountain, Kharkov Ferozpur road, Lahore
Squares:
Public Square
• An area with pavement or grass and trees for public refreshments (Mesqel Square).
• Need for breathing space for cities,
• The need for public meeting and open spaces and
• Improvement of urban scene and quality
Traffic square
• Facilitation of mobility (Gotera Square),
• Formation of traffic Safe junctions and
• As landmark for places Interchange square
Public Square
Market area
Plaza of public
buildings
Enclosed places by
buildings Fig. Meskel Square, Addis Ababa Fig. Times square, New York
convenient for
recreation
Commonly found
with public
buildings, road
junction,
monuments
Larger for bigger
cities Fig. Verona public square at front of a cathedral
Traffic Square
Types
•T-Junctions
•Cross- Fig. Gotera, Addis Ababa
Junctions
•Roundabouts
•Grade- LAYOUT A
Separated LAYOUT C
Junction
LAYOUT E
Fig. Kennedy Cloverleaf, Chicago
Size and Level of services
Size of public square depends Size of traffic square also depends
on the location: on the location:
Level of public concentration: the Street hierarchy: arterial streets bigger cross-
more public concentration implies section with larger traffic square.
larger sizes.
Centrality: main centres with larger Number of roads accessing the square:
public square. directly proportional.
Level of service: depends on its size. Level of service depends on the hierarchical
sizes.
Provision of good square/plaza

Requirements of public square/ plaza
• Good accessibility,
• Enclosed and active space,
• Location around the public concentration areas and better form/ aesthetics,
• Provision of amenities (seats, walkways, water features, plants, etc.),
• Should be Developed according to standards and regulations and
• Should not promote dangers (sufficient space for the pedestrian traffic).
Provision of good square/plaza
Fig. St. Peters square, Rome

•A well equipped square
•Well organized with subordinate
spaces
•A reception place for St. Peter’s
Cathedral
•Provision of focal point at the middle
Fig. Design of 404 Square, Hawassa old central area
• Integration of public plaza with traffic square,

• Active public area with commercial and public institutes and
• Existence of focal point from the plaza.
Similarity and differences of nodes and squares
Node Square
• A junction of paths/ convergence of • May be at junction of paths,
paths, • An open space for public meeting,
• Strategic spot in to which observer refreshment, pray,
enter, • Scale depends on the level of the public
• Scale varies from local area to and activity concentration,
urban, region, country, • Can be traffic junction facility or public
• Nodes can be large squares or concentration, square, geometric shape,
extended linear shapes of public area, • Squares are found with public buildings,
• Nodes are places at which decisions road junction, monuments and may not
be a place of decision for mobility.
are made (junctions and break in
Nodes in a region
• Region is a large land area that has geographic, political, or cultural
characteristics which distinguish it from others, whether existing within
one country or extending over several countries.
• Conceiving the setting at a national or international level, then the whole

city may become a node in a region.
• Nodes are places at which observers perceive nearby elements with more
than normal clarity.
• It is a change of condition on the way with more activities that can
specifically mark the area.
Factors for the identification of nodes
Global/ regional scale nodes
• Higher level of economic, political, and other related influences;
• Transport network importance (airline, railway, road, water way links);
• Population concentration; the higher pop. Size higher importance or level.
• Attractions for global/ regional scale travelers: cultural, historical tourist, and
other values and etc.
Urban scale nodes
• Number and size of commercial facilities;
• Existence of important public services (school, religious, cultural, administration,
etc.);
• Access to transport network level (No. of road, rail, … links);
• Availability or level of public transport linkage
The hierarchical Global/ Regional/ City nodes
• Globally the world scale business, political and tourist destinations are:
• New York, London, Tokyo, Paris, Berlin, Brussels….
• African Regional nodes are:
• Addis Ababa, Johannesburg, Cairo, Abidjan
• Ethiopian scale nodes:
• Addis Ababa, Dire Dawa, Harar, Gonder, Bahir Dar, Adama, Jimma, Hawassa,
Mekele, Dessie, etc.
• City level nodes:
• Wollega university, Board, Meskel square, Mazoria 1, Mariam sefer…
• In some special cases it is not only an urban center that can be a node.
• Places like Dalol/Ert-ale, Sof-oumer, Tis-Abbay or other religious festivity sites
can be important nodes.
Global Mega cities as node
Global Mega cities as Node Fig. London
Fig. Paris
Fig. Berlin
Important nodes in Ethiopia Regional nodal areas
• Addis & its surrounding,
• Adama & its surrounding,
• Harar- Dire Dawa area,
• Hawassa-Shashemenne area,
• Jimma & its surrounding,
• Bahir Dar & its surrounding,
• Gonder & its surrounding,
• Mekele & its surrounding,
• Dessie-Komblch area,
• Asosa area and etc.
The areas shaded in dark red show the bigger

urban centers and regional node of Ethiopia.
Important nodes in Addis Ababa
Merkato,
Lega-har,
Megenagna,
Bole,
Torhayloch square,
Ashewa Meda,
Mexico,
Meskel Square
Important nodes in Nekemte
Wollega university area,
Mazoria
Board
Katanga
Jitu
Mariam Sefer
Meskel Adebabay
Bus station
Urban Nodes
Assignment One
Identification and analysis of nodes in sections of Nekemte City.
Nodes- between _______________ to _________________
Classify them in to three hierarchies

a. City Scale Nodes (level 1)
b. Local Scale Nodes (level 2)
c. Specific Area Scale Nodes( level 3)
Note: Identification of the main urban forms (buildings, streets, monuments, public spaces).
Analysis is undertaken through studying the morphological arrangements of the elements.
The diversity and significance of the activities.
Use Sketches and hybrids for mapping and images.
Urban Nodes
Examples
Urban Nodes
Examples
Urban Nodes
Examples
Trends in Urban Formation/ Urbanization
Trends in urban formation/ urbanization
Definitions:
• Urban is the positive action of human being on spatial developments.
• Urban is spatial settlement contrasted to rural settlement.
• Urbanization is the dominant process in the spatial organization of the
world’s population.
Causes of urbanization/ nodes
• Establishment of religious institutions (Lalibala).
• Development of infrastructure, especially roads (Dire dawa ).
• Formation of political/ administrations centre (Addis Ababa).
• Establishment of economic centre: production/ industries, market
places (Kombolcha, Dukem, Bishoftu,).
The most common factors of urbanization by Leonard Reissman (1964):
• Economic development: Results in the movement of people from
agricultural communities into larger and nucleated non-agricultural
communities.
 Agglomeration economies: Highly related to economic development,
but particularly refers to the concept of growth as cumulative and
cyclical. Larger cities attracts sustained/rapid growth.
• Political and social changes: Are believed to be important forces of
urbanization.
Factors for speeding up of urbanization Which one of the following is NOT considered as the
major factors of Urbanization.
• Economic development. A.
B.
Economic Development
Formation of agricultural communities
C. Emergence of administrative classes
• Formation of large non-agricultural communities. D. Localization of special skills
Answer: B
• Emergence of administrative class.

• Development of crafts, arts, etc.
• Extension of trade and the localization of special skills.
These factors in turn include :
• Associations exist between economic level & urbanization.
• Demographic factors: larger population can contribute more.
• Agglomeration economies: once a large city is created then the attractions are
higher.
• Political and social changes: first urbanization and then industrialization is the
general truth.
The size scale in urbanization:
• The size of urban centres vary from hamlet to megalopolis.
• The size of urban agglomeration is increasing and there seems to be no
limitation on urban growth.
The size scale in urbanization cont…:
• The largest urban agglomerations are growing at fastest rate.
Source: UN-Habitat
The size scale in urbanization cont…:
• In industrialized countries, major restructuring of the population
distribution (inner cities are showing a loss of population by
outmigration).
• Some of the oldest metro-poles are showing overall decline.
Opportunities of urbanization
Urbanization is often associated to:
• Civilization, Development and
• Technological advancement
Cities are: Engines of economic growth, Agents of social & cultural transformation and
Places of innovation/technology
Urban areas account for greater proportion of GDP in many countries.
• Places of economic efficiently and Enable to earn maximum return from limited
land resource. Area= Singapore-724.2 km2/ Addis Ababa
Ababa-527
527km2
km2
Urban Functions
• Central place functions or general services: carried out for a more or
less extensive but contiguous area.
Urban Functions cont…
• Transport functions: carried out at break of bulk points (loading -
unloading points) along the major routes of communication.
Urban Functions
• Special functions: those are carried out for non- local and non-contiguous
areas.
Characteristics of Trends of urbanization: Which of the following is true about the
trends of Urbanization?
A. Urbanization is an old phenomenon
B. Currently the rate urbanization is
• Recentness of urbanization: before the start of the 19th century only
declining
3% (2021, 56%), recent observable fact, C.aUrbanization
feature is of mostthe lastin one
noticeable
developing counties
hundred and fifty years. D. The trends of Urbanization is shifting
from south to North.
Answer: C
• The dominance of urbanization: The today’s accelerated world
population growth is its even faster urbanization. In 1960 to 1970 urban
growth has reached over 40% per decade and today more than 55%.
• The location of urbanization: urban growth is most noticeable in

developing countries. ‘millionaire cities‘ are increasing in number and
also there is a shift from north to south.
Summary of trends in Urbanization
Field of Trend Background Implication
1. Population Decline of birth rates; Unbalanced demand for public

Ageing of population infrastructure;
High demand for health and other
social services;
2. Migration Continuing rural to urban Housing and employment problems
migration in less in target and gateway cities in
industrialized countries; prosperous regions
International migration
South-North and East-West
Summary of trends in Urbanization cont…
3. Households/ life Decreasing household’s sizes; New social networks,
styles neighbourhoods relations,
locations and mobility
 Higher labour force patterns;
participation of women;
Need for new services and

Reduction of work hours; new new housing, land and
life styles. transport policies.
4. Economy Reorganization of Increased competition between cities;
production and
distribution;
Innovation oriented local economic
policy;
Polarization of firm sizes;
Technology centres and parks;

 Liberalization ,
deregulation, privatization,
internationalization Intra and international disparities, social
tensions and eroded public services.
5.Transport/ Technologies change, stimulates Further dispersed urban
communication personal mobility and goods development;
movement;
Efficient public transport in

Road transport dominant; small and medium sized
cities is difficult;
Growth of high –speed rail , air

transport, telecommunications.  Polarization between
industrialized and less
industrialized countries.
6. Environment/ Transport and industry  Cities in fast growing and

resources generated pollution; developing countries affected
 Car restraint
Energy conservation,  Anti-pollution
 Energy conservation
 Land use control policies are
required
Theories of Urban System
Theory: A scientifically acceptable general principle or body of principles offered to explain phenomena.
Models: Representation of a phenomena, a simplified description.
Different theories and models have been developed and introduced to
explain:
• The evolution,
• Spatial arrangement,
• Size structure,
• Function and characteristics of urban systems/urban centers.
The theories and models are intended mainly to establish regularities and
peculiarities of urban systems, with greater emphasis on the former.
Some of the very common theories/models are;
1. The garden city concept:
Refers to an ideal
• Self-contained community of predetermined area and population surrounded by
a greenbelt.
Developed by E. Howard (1898) –in the name of ‘Social Cities’.
Later the name is changed to ‘Garden Cities of Tomorrow’.
The model that has practiced in more than 70 countries.

1. The garden city concept cont…:
Diagram 1 Diagram 2 Diagram 3

1. The garden city concept cont…:
Diagram 4 Diagram 5 Diagram 6

1. The garden city concept cont…
 Spatial arrangement cities as
diagram.
 Intended to bring together the

economic and cultural advantages of
both city and countryside.
 Similarity with classical cities.
 Hierarchical arrangement of nodes.

1. The garden city concept cont…
• City as diagram and perfect
geometrical Shape.
• Garden city would house
32,000 people on a site of
9,000 acres (3,600 ha).
• The garden city would be self-
sufficient.
• When it reached full
population, another garden
city would be developed
nearby.
• Overcoming overcrowding
and deterioration of cities.
2. Central Place Function and Central Place theory:
• Central place theory was developed basically from the concept of central place
functions. (humans tend to purchase goods from the closest place).
• Regardless of their size, urban settlements emerge or exist for the efficient
performance of functions for the community.
• Developed by W. Christaller in 1933 based on empirical evidences obtained from
Germany.
• It is the establishment of conceptual framework that explains the relationship between
and among;
• the size, rank, number, spatial arrangement and functions of urban centers.
• It includes the interdependence within the urban system.
• The urban and farm population would be dispersed in an even pattern.
• Central places are not only for services but also as physical centers.
 Developed by Christaller, in
1933.
 Space covering hexagons for

a set of market centers of
same order.
 Equi-distant centers with 5

hierarchical order.
 Services of hexagonal non-

competing market areas will
emerge.
3. Models of Urban Size Structure:
There are three models of urban size structure:
a) The rank - size rule.
b) The law of primate city or urban primacy.
c) The general rule of urban size structure .
• The reverse is true for the relationship between the size/rank of central places and
the size of their respective hinterlands.
• Law of the primate city (A city is much larger the 2nd larger city).
• Towns of the same size will be evenly distributed and larger towns will be further
apart than smaller ones.
• Towns are mutually interdependent with functional diversity.
3. Models of Urban Size Structure cont…
Top ten urban areas by population
The 10 Bigger cities distribution in the The 1500 towns distribution in the country
3. Models of Urban Size Structure cont…
Distribution of small towns (closer to each other)
4. Spot- axis theory: -
It is part of regional growth theory.
Spot refers to poles/nodes and axis refers to spatial pattern, mainly

transport, communication and linear infrastructure lines.
Spot and axis are important factors forming the network of economic
activities.
Axis acts as channels of polarization and diffusion.

Spot Axis
A uniform plain assumption of urban spatial

pattern
5. Growth pole theory (F. Perroux 1955):
• Perroux argued that growth doesn't occur any where at the same time and pace.
• Growth starts at some growth spots/ poles with varying intensity.
• The process involves, first polarization and then diffusion through different
channels.
• The influence of growth poles in regional economic development.
• It applies to the influence of urban places with varying size on their respective
hinterlands.
5. Growth pole theory (F. Perroux 1955) cont…
Growth Poles and their Developments

• Francois Perroux defined growth poles in terms of what he called abstract
economic space.
• He assumed it does not correspond to region or city.
• Perroux conceived of abstract economic space to be of three types:
• An economic plan
• A field of force or influences
• A homogeneous aggregate
• He denied that abstract economic space could correspond to a geographic
area: like city or region.

• For Perroux the aspect of dominance was important for growth poles (eg.
Out put A>B)
• Perroux and other writers based the concept on the notions of external
economies, agglomeration and linkages.
• An external economy exits if a change in the output of one firm or one
industry affects costs in other firms. (+ve, -ve)
• Linkage is a concept developed in regional economics.
• Growth poles are geographic as many of the applications of the concept
are for geographic regions.
• The regional economy of a city or an area can be considered to be a growth pole.
• The process of development of a propulsive firm or industry is called polarization.
• The effect of polarization on the surrounding geographic area is not always positive.
• Positive
• Economic opportunities.
• Technological advancement.
• Negative
• Loss of balance.
• Problem of development management.
• Trickling down of surrounding regions.
• Growth poles are also interpreted as ‘engines of economic, social, and
cultural developments’.
• Level of such poles as to economic space:
• Growth poles,
• Strong poles,
• Growths,
• Weak growth,
• Substandard growth,
• Negative growth
Read on more theories of urban planning:
Modernist planning:
Physical planning: • Systems theory,
• Sanitary movement, • Rational process approach,
• Linear city,
Models • Incrementalism,
• City Beautiful movement, • Concentric Zone model, • Mixed scanning model,
• Towers in the park, • Linear Model, • Strategic Urban Planning,
• Decentralized planning, • Sector Model,
• Land-Use Planning,
• Grid model,
• Multiple nuclei model, • Master Planning,
• Urban Realms model, • Urban Revitalization,
Post-Modernist planning: • Core frame model, • Economic Development,
• Broadacre planning, • Environmental Planning,
• New urbanism, • Infrastructure Planning,
• Strategic urban planning, • Public choice theory,
• Smart growth, • Bid rent theory,
Urban Nodes
Assignment: Two
Weight :10
Submission date: January 11, 2022
Identification and analysis of nodal areas Nekemte City (city scale only)
Activities:
1, Identification of Nodal Areas of Nekemte
2, Important Nodes and Their Importance ----- Factors (their services, activities…)
3. Distances between them and their implications
Urban Nodes
Assignment: Three
Weight :20 Submission date: January 18, 2022
Develop nodes on the road segment you previously assessed by selecting one of the
nodes.
Factors for design:
1. No of connections through public arterial/ collector roads
2. Current transport terminal or station on close distance areas
3. Existence of public services access ways from the point
4. New development prospects in the near future that is under-construction, planned,
to be planned developments
5. Its distance from next nodes.
Note: The design needs to include rearranging the physical arrangement of the node.
Use sketch or hybrid for your design, try to indicate all of the physical components
and explain them.
Urban
example
Nodes
example
Transportation node
Public square and space
Commercial or
Service District
The Process of Urbanization in Regions
Defining urban areas
In some development areas it becomes difficult to identify or portray the areas. It is
very difficult to compare the intense urbanization taking place within developing
countries in a few short decades with the gradual urbanization took place over
centuries in the developed countries.
This is due to the following basic reasons: -

• Lack of standard measurement
• The settlement continuum
• The changing concept of urban character
• The inadequacy of official designation

Lack of standard measurement
It can really depend on one’s country’s or urban area’s level of urbanization.
Examples:
 InWhich
Ethiopian context
of the following urban
is NOT is anasarea
Considered thatto has
a criteria defineaturban
leastarea2000
in residents and their
Ethiopia? depends at least 50% on non agriculture.
livelihood
A. Population size not less than 2000
 InB.USA is a continuously
Population built-up
density of 1,000/1.6Km square area with a population of 50,000 or more. At
least
C. comprising density
Continuously built up areasofwith
1,000 population/
the population 1.6 km square.
of 50,000
D. Urban land use type that does not allow any gaps
 InAnswer
European
A countries Urban-type land use, not allowing any gaps of typically
more than 200 meters.
 Most Asian developing countries define urbanization by population.
 Some countries define urban area through administrative declarations.
The settlement continuum:
No point in the continuum from large agglomerations to small clusters is there where
urbanity disappears and rurality begins.
Suburb (old use), Sub-town and Villages (of 300 and more with urban functions)
Addis Ababa
Sebeta
The settlement continuum cont… Solutions
• Inter – Regional and Intra- regional planning
 Provision of infrastructure
• Regional Economic Planning
 The injection of investment
• Metropolitan Level Governance
 (Metro Manila that contains 17 local cities,
Greater London with 7.5/20 million people,
City of Toronto 2.5/5 million people.
• Regional Disaggregation of National Plans
• Regional Land- Use Planning
• Natural Resource Planning
The settlement continuum cont… Solutions
• 6 municipalities
The changing concept of urban character
• In the medieval time the walls were the barrier between urban and rural
areas.
• Urban agglomerations (other towns as part the central town/ city).
• Urban and urban districts/ quarters.
In some cases, at the system of central places, centers are scaled into five sizes:
• (hamlets, villages, towns, cities and metropolis)
The idea of certain minimum collection of functions to define what is urban

became not important.
The inadequacy of official designation
• Most countries have formal means of identifying what is urban.
• Some being based on legal title that is neither statistical nor functional factors.
• Some try to relate urban to functional factors of the spaces.
• Some consider the boundary to include potential land at proximate area of the built
up areas.
• In general, these points indicate existence of lack of clarity and consistency in

setting urban boundary.
Patterns of urbanization
• Historically, the most important urban growth was started in the Middle
East.
• Urbanization has contributed to the varying results of technology like:

• Technological advancement, metal ware/ works,
• Water resource management
• Standardization of measurement
• Time measurements, seasons, months, days, hours
• Stimulation of writing: teachers, doctors, magicians, diviners
• Rise of military
Patterns of urbanization cont...
• According to the UN estimates these days: -
• More than 55% of the world population live in cities/ towns.
• More than 80% of the industrialized countries live in towns/ cities.
• Only three of the largest cities (Tokyo, New York and Los Angeles) are found
industrialized countries.
• This implies high population concentration in less industrialized countries.
• In reference to urbanization, Europe and North America are at the top location
Patterns of urbanization cont...
• European countries take the leading status in urbanization level.
• African countries are mostly with least urbanization level.
• Bigger urban centers / global cities are distributed irrespective of economic

powers in populous countries.
• According to UN, urban agglomerations include:
• All contiguous territory inhabited at urban density levels,
• It is without regard to administrative boundaries.
• It includes people living outside the official boundaries of a city or
administrative district
Temporal Level of world urbanization
Level of urbanization in the word over time (temporal trend)
•1800 - 3% of world population was living in towns/ cities
• 1900 - 14% `` `` `` `` `` `` `` ``
• 1950 - 30% `` `` `` `` `` `` `` ``
• 2000 - 47% `` `` `` `` `` `` `` ``
• 2030 - 60% `` `` `` `` `` `` `` ``
• Netherlands is highly urbanized (89%) and industrialized.
• Ethiopia is one of the least urbanized (17.8%) and one of least industrialized
countries.
Urban centres classification:
The common classification of urban centers is based on two factors: -
• The population size order.
• Urban function classification.
The population size order: -

• It simply focuses on the population size that is focus level is proportional to the
population to be served.
• The bigger the population is the greater the rank.
• Case of Ethiopia: - Urban levels, 1,2,3,4,5
• Such classification undermines the functional role/s of urban centers.
Urban function based classification:
This classification is based on the descriptive performance of cities.
Accordingly, there are six groups:
1. The Metropolis and / megalopolis: - a large city usually population more
than a million/ 10 million.
2. Manufacturing towns:- towns dedicated mainly for industrial
development (agro-processing/ others)
3. Service focused towns: admin., edu, health…
4. Populous seaport towns:- bigger cities at ports
5. Great watering places:- urban developments water dominated lands
6. Others urban centres:- towns of less importance
Urban function based classification cont...
• Hierarchy is level of importance compared to other urban centres.
• Most urban centres posses the highest population size and top hierarchy in a
country.
• Some are with small population and top hierarchy.
• Some are with large population and less hierarchy like Sao polo of Brazil.
• In most cases population size has the most dominant role than function.
Ranking of Urban Centers
Units of study adopted for ranking urban centers
Levels of investigations includes population size for ranking of urban centres
1. Population size: by categorizing population with certain number

(thousands,10,000s , 100,000s, millions)
2. The towns service level investigation: Includes all the services in the town.
3. The commercial core level: Center of the town with all kinds of
commercial/ economic functions.
4. The retail center: Concentrates on the number of retail trades (clarity of the
retail trades? Area?)
Units of study adopted for ranking cont...
5. Level of connection: To other cities and regions which includes the
infrastructure type (road: asphalt or gravel, rail line, air lines,).
Which of the following is NOT considered as a criteria for
ranking urban centers in Ethiopia?
6. Tourist attraction level: ExistenceA. of historical
Population or town/cities
size of the other tourist attraction
elements. B. Administrative role
C. Service level of the town
D. Level of separation from other town/city
7. Administrative service role: Which includes; kebele, woreda/ district, zonal,
regional, national admin. Roles.
8. Hinterland potential: Fertility of land, population pressure, etc.

9. Distance from other bigger / small towns: bigger cities have mostly negative,
smaller ones positive effects on the growth the specific town/ city.
• This evaluations have their own weakness to identify the vital points as it
imply same urban development condition in different countries.
E.g. In some countries there are other factors more important than the retail
and commercial centers.
• Other schemes of town ranking:

• The inclusion of all city facilities rather than an arbitrary selection
(extended list of facilities, total no.)
• More rigorous/exact procedures in the identification of ranks (more
objective though points)
• It is known that in simple mentioning, population size is the most
important factor.
World’s largest cities in 2003 by Agglomeration
1 Tokyo, Japan 35 million
2 Mexico City, Mexico 18.7 million
3 New York, United States 18.3 million
4 São Paulo, Brazil 17.9 million
5 Mumbai, India 17.4 million
6 Delhi, India 14.1 million
7 Kolkata (Calcutta), India 13.1 million
8 Buenos Aires, Argentina 13 million
9 Shanghai, China 12.8 million
10 Jakarta, Indonesia 12.3 million

World’s largest cities in 2003 by Agglomeration cont...
11 Los Angeles, United 12 million
States
12 Dhaka, Bangladesh 11.6 million
13 Osaka, Japan 11.2 million
14 Rio de Janeiro, Brazil 11.2 million
15 Karachi, Pakistan 11.1 million

16 Beijing, China 10.8 million
17 Cairo, Egypt 10.8 million
18 Manila, Philippines 10.4 million
19 Paris, France 9.8 million
20 Seoul, South Korea 9.7 million
Source: UN Population Division.
Largest Cities of the World - (by metro population) 2010
1. Tokyo, Japan - 32,450,000

2. Seóul, South Korea - 20,550,000
3. Mexico City, Mexico - 20,450,000
4. New York City, USA - 19,750,000
5. Mumbai, India - 19,200,000
6. Jakarta, Indonesia - 18,900,000
7. Sáo Paulo, Brazil - 18,850,000
8. Delhi, India - 18,680,000
9. Õsaka/Kobe, Japan - 17,350,000
10. Shanghai, China - 16,650,000
Largest Cities of the World - (by metro population) 2010 cont...
11. Manila, Philippines - 16,300,000

12. Los Angeles, USA - 15,250,000
13. Calcutta, India - 15,100,000
14. Moscow, Russian Fed. - 15,000,000
15. Cairo, Egypt - 14,450,000
16. Lagos, Nigeria - 13,488,000
17. Buenos Aires, Argentina - 13,170,000
18. London, United Kingdom - 12,875,000
19. Beijing, China - 12,500,000
20. Karachi, Pakistan - 11,800,000
• Weighing the size of facility or establishment (floor space, users, etc)
• Establishment. (No. of shops as elementary value)
• Functions. Counting each outlet by function (units doors)
• Functional units (Counting each outlet (units doors) regardless of type
• In Britain by counting no. of bank branches, publication of news paper, cinema, &
school
• A=three banks of major ones
• A’=three bank branches,
• A’’=two bank branches,
• B=School,
• B’=only one of the above,
• C=Cinemas,
• C’=D + one of the above and
• D= publication of news paper.
Ranking of Urban Centers- Ethiopia
Urban Level Classifications
Which of the following is a correct sequence about urban level classification of
Ethiopia
A. Small Towns  Medium towns  Cities  Large Towns  Metropolitans
B. Small Towns  Medium towns  Large Towns  Cities  Metropolitans
• Level 1- Small Towns ----------
Answer: B with population from 2000 to 20,000
• Level 2- Medium Towns ---------- with population of 20,001 to 50,000
• Level 3- Large Towns ---------- with population of 50,001 to 100,000
• Level 4- Cities ----------- with population of 100,001 to 1,000,000
• Level 5- Metropolitans ----------- with population over one million

Draft Ranking of urban center
Metropolitan city
• Population more than 5 million
• Refers to Addis Ababa
• Sub-city level municipality
Regiopolis (primary) city
• 26 cities (excluding AA)

• All the 9 regional capitals including Dire-Dawa
• Urban plan similar to AA.
• Those towns with population up to 19,999 in the 2007 census
Draft Ranking of urban center cont…
Secondary cities
• 18 cities
• They are expected to attain regiopolis (primary) level
Tertiary cities
• 41 remaining cities/ towns
• Population: 20,000 and more
Urban villages
• Those towns with population less than 19,999 in the 2007 census
Rank Order of the Eleven Ethiopian Biggest Towns by Population in Different Periods (1938-2013)
City Pop 2007 City 2013 Pop 2013
Pop City Pop City City
Rank City 1938 Pop 1984 Pop 1994 Pop 2000 2007
1938 1967 1967 1984 1994
1 Addis Ababa 300,000 Addis 644,190 Addis 1,412,575 Addis 2,084,488 2,570,004 Addis 2,710,000 Addis Ababa 3,103,999
Ababa Ababa Ababa Ababa
2 Harar 45,000 Dire Dawa 50,733 Dire Dawa 98,104 Dire Dawa 164,851 227,494 Dire Dawa 233,224 Mekelle 286,624
3 Gore 25,000 Harar 42,771 Adama 76,284 Adama 127,842 166,000 Adama 220,212 Adama 282,974
4 Dire Dawa 20,000 Dessie 40,619 Gonder 68,958 Gonder 112,249 156,087 Mekelle 215,914 Dire Dawa 269,134
5 Jimma 15,000 Gonder 30,734 Dessie 68,848 Dessie 97,314 135,529 Gonder 207,044 Gonder 264,964
6 Gonder 14,000 Jimma 30,580 Harar 62,160 Mekelle 96,938 134,996 Awassa 157,139 Awassa 225686
7 Mekele 12,000 Adama 27,812 Mekelle 61,583 Bahirdar 96,140 134,062 Bahirdar 155,428 Bahirdar 198,909
8 Debre Markos 12,000 Mekele 23,105 Jimma 60,992 Jimma 76,378 125,569 Jijiga 125876 Jimma 155434
9 Jijiga 11,000 Bishoftu 22,005 Bahirdar 54,800 Harar 76,378 126,000 Jimma 120960 Dessie 153691
10 Axum 11,000 Deber 21,536 Akaki 54,146 Bishoftu 73,372 103,569 Dessie 120,095 Jijiga 152674
Markos
11 Nekemte 10,000 Axum 13,905 Bishoftu 51,143 Awassa 69,169 98,917 Shesheme 100,454 Sheshemene 129084
ne
1. Primacy condition? , 2. Declining and flourishing cities/ towns?, 3. Distribution/ location?

The Need for City Networks
City networks
A, A cooperation and connection on different common issues.
• Benefit of connections
• information flow,
• practice exchange,
• innovations in projects and
• financial management.
• Forces for city networks
• Functions of urban regions,
• Holistic city planning,
• Thinking it all services through development &
• Finding benefits for all.
B, The consistency to keep the pace is not continuous.
• The network fails to function, specially, in the developing countries.
• Urban growth and decline, factors affecting growths:

• Population density on the surrounding,
• Activities decline,
• Climatic conditions,
• Political focus and
• Accessibility.
Problems of urbanization
Some of the common and selected critical issues
• Anomie and alienation
(being unknown and unfriendliness).
• Lonely crowd,
(superficiality, lack of sentimental and emotional ties).
• Urban blight and poverty:
(unemployment and being poor)
• Decaying
(inner city areas).
• Peripheral slums (bidon-villes of developing countries).
Problems of urbanization cont...
• Transport systems: congestions and delays.
• Pollution: -air, solid and liquid wastes pollutions,
• Vulnerability of certain groups,
• Anonymity, violence, and crime,
• Finance: - loss of tax, need for huge expenditure to keep itself going and
• Administration: - lack of good governance

Planning of Growth Poles
The planning need to consider the factor for the economic growth strategies:
• An economic plan of the region: based on the availability of resources and

strategic linkages.
• A field of force or influences: Areas with strong force of economic

importance, for example:
• Basic industries areas/centre.
• Secondary/ medium industries area.
• Small scale industries.
• A homogeneous aggregate: polarization and disparity should be reduced or

avoided.
Planning of growth poles in the spatial aspect need land development policy
• Direction setting: the issues, scenarios, goals and visions of the community
report.
• Formulating a system of land policy classification: policies classified into
three basic types
I. Conservation areas/ districts: -significant, scarce, or irreplaceable
natural, recreational, scenic, and historic resources
These include:
1. Areas of critical environmental concern
2. Agricultural reserve, forestry, other production oriented areas
3. Other such areas
Planning of growth poles in the spatial aspect need land development policy
cont...
II. Urban-settlement areas/ districts: Urban growth area with necessary

mixes and development elements.
1. Developed districts
2. Developing or growth districts
III. The rural area/ districts: - areas of less intense development

pressures. It includes:-
1.Community centres (low density)
2. Rural holding districts (development in long range)
3. Agricultural reserve, forestry, other production oriented areas
Shapes of Cities and Formation of Nodes
Linear shape
• Urban form shaped by road infrastructure
• Nodal developments are in response to community reach
• The middle one gets more impetus of growth
Which types of city/town
Concentric shape shape is created when a
• Shapes due to absence of constraint city is split out
into separate distinct due
• Nodes most likely at physical center to the existence of
constraints within its
Stretching-out shape boundary?
• Shape formed following infrastructure A. Concentric
B. Linear
• Multi- node as parts are far apart C. Stretching out
D. Fragmented
Fragmented city shape Answer: D
• Split towns due to constraints
• Nodes formed at separated parts
• General categorization of cities/towns

• Mono-centric
• Poly- centric
• Mono-centric towns are smaller

size and contain concentration of
important activities at one point.
• The common activities of such centers
include: markets, religious services,
public gathering places, etc.
Mono-centric character is developed due to:
• Development/emergence of urban center around single public function like religious
service or market.
• Formation of traffic lines junction, development of activities around the point.
• Planned formation of mono-centre where activities are placed around single point.
• Existence of sea/ lake ports.
• Physical character of the land.
Location of the centres/ nodes

• At the physical centres.
• Along the most accessible transport axis.
• At existing most developed centre.
Centers location in mono-centric areas (urban/ region)
1. Physically central location 2. Location at the edge of the area
3. A centre located at one corner 4. Shifted location from physical centre

Shapes of mono-centric towns
• Star: intersection of radiating lines
• Along linear dev’t: a line with housing and

service centers
• Junction/ intersection: two roads and activities
• Concentration points: at the end of linear

developments
Location of the centres/ nodes in a city
Mono-node/ centre
 A single node or centre of a town.
 A centre for small town.
 Concentration of central functions at one point :
• Services,
• Commerce,
• Administration,
• Recreation and
• Religious center.
Location of the centres/ nodes in a city
Poly-nodes
• Hierarchical distribution of nodes,
• Higher order services, commercial functions, etc. at
major centre and
• Smaller scale services at local centres and nodes
• Major centre at the major existing node.
• Along the most accessible transport axis.
• At a position it can easily be connected to other smaller centres.

Character of Poly-centric Cities
• It implies the existence of two and more centers in a given city or urban region.
• The category includes urban centers of different sizes (bigger and small
population sizes).
• The nature of the poly-centers within a city/town can vary from similar centers
to varying sizes:
1. A bigger center and supportive ones,
2. Hierarchical sizes of the centers and
3. Similar centers.
Character of Poly-centric Cities cont…
Similar A bigger center and supportive ones: is center development without
clear hierarchy. Centers are distributed within different parts of a city/town.
Hierarchical sizes of the centers: Such types of centers are mainly results of
planned urban developments.
• The arrangement is based on concentration of activities with order of public
importance.
Example:
• Market hierarchy (main market to small ones, market of 10,000 and
1,000 attendants).
• School distribution (No of users and hierarchy).
• Municipal services and administration hierarchy, etc.
Character of Poly-centric Cities cont…
A bigger center and supportive ones
• It is a concentration of higher public services in one main center and minor
developments of public amenities.
• The character may be developed in planned and semi-planned types of urban
developments.
Shapes of Bigger Center and Supportive Ones
• Star: with centers along radiating lines.
• Radio-centric: centers at intersection of radiating and ring lines.
• Satellite: Similar to star but not always along radial lines or rings.
• Linear: Concentration of centers along single line/ road.
• Rectilinear: centers developed on a iron-grid type street network
Types of Arrangements of Bigger Center and Supportive Ones
• Branch: It is commonly a developed on physically dictated topography.
• Sheet: It can be a planned or unplanned type where the roads arrangement is

mix of organic and iron-grid types.
• Constellation: Centers location in a planned development where the end of the

roads can be converging in different directions.
Arrangements of Poly-nodes
The shapes are dictated by:

• The existence and arrangement of road
intersections.
• Existence of constraints.
• Patterns of development planned /
unplanned.
Arrangements of Poly-nodes cont… 1
1. Rectilinear
Shapes for formation 2. Branch

of hierarchical Centers
3
3. Sheet
4. Constellation
Arrangements of Poly-nodes cont…

Similar centers in a town
• In such urban development there is no special concentration of activities at
single point.
• Similar activities levels are found in each center.
• Shapes of such centers include:

• Linear developments along a road and developments of centers along a
single ring road.
Types of Specific Function Nodes
• Traffic Nodes:-
• Terminals, stations, stops, with activities
• These are points at which transport breaks, people concentrate and activities emerge.
• Commercial Nodes:-
• Markets, shopping centers, cafes, Restaurants, Hotels and their
specializations
• Services Nodes:-
• Entrance areas of schools, Hospitals, Religious services, cultural center, etc.
Mapping land and designing nodes: -
• After the land strategy districts are decided, the areas shall be drawn on
maps.
• All the necessary rules, regulations, and polices need careful

consideration.
• Tasks include deriving principles, map location suitability, estimate

space requirements, analyze holding capacity and design the future
urban form.
Urban System Planning
The urban system plan aims at:
• Promoting harmonious development of urban place at different sizes.
• Reinforcing the regional development pattern in a sustainable way.
• Providing basis for the preparation of urban plans for individual urban
centers within a region
Three important components
• Size structure plan
• Functional structure plan
• Spatial arrangement/structure plan
Urban System Planning
Basic contents and procedures of urban system planning
• Appraisal of comprehensive conditions of the urban development in the

region.
• Comprehensive appraisal of the urban development condition (city

based).
• Formulation of regional urban development strategy.
• Forecasting of regional population growth and urbanization level.

Physical Regional Planning

Planning of Nodes:
• Identification of existing nodes and their problems, hierarchy, network, etc
• Analysis of the growth of city/ town,
• Analysis of trends of the region,
• Identification of major functions,
• Determining Number of Nodes/ cores,
• Boundary and Network definition,
• Organization of the nodes (hierarchy and physical orders) and
• Articulation of the elements.
Regional Nodes Planning
Assignment Four
Prepare Regional schematic plan of the given region

• The centres should have min. 6km and max.12
• Hierarchical status 30-50km apart for the higher ones
• Population threshold 2000
• Special consideration should be given for villages on major roads and far from
other towns
• Consider more developed has more growth
• Accessibility level has significant effect

Regional Nodes Planning
Assignment prepare schematic plan of the given region
Given:
• East Wollega and West Shewa
Requirements:
• Maps of existing situation (network, Admin., pop.)
• Proposed networks
• Proposed urban ranks
• Text report on the potentials for growth (for the rank maximum two pages)
Thank You!

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INSTITUTE OF TECHNOLOGY DEPARTMENT: URBAN AND REGIONAL PLANNING

COURSE TITLE DESIGN OF URBAN AND REGIONAL NODES

• Concentration of people, activities, etc. A.

• This definition refers to urban or rural centers.

• In all events, nodes are dominant features in urban developments.

• Nodes may be simple public or activity concentration point.

• Nodes gain importance due to condensation of some uses or physical characters.

Example: - street corners, hangout or enclosed squares.

• Naming of spaces as node depend on the scale of observation.

• Nodes may be called cores (centers).

• Urban nodes: - Traffic, commercial, social service centers, public centers,

• Rural nodes: - Service centers, production areas, markets, etc.

• Specific area nodes: - Junctions of paths, shopping centers, service centers,

Eifel, Paris Saint Basil Cathedral, Moscow

Classification of down town spaces/ criteria

• Paths/roads/ streets: channels of observers where

• Edges: ends of lines, ends of walls, shores, etc. They

A point of reference external to the

Land marks: Points of references, external/ not

Corporate Foyers: Part of a new generally high rise building complexes.

• Nodes are accessed by observers.

Examples of land marks:

• Public square is an open, usually four-sided area in a city or town where

• Traffic square: is a road or railway junction at which two or more lines

Provision of good square/plaza

Fig. St. Peters square, Rome

Fig. Design of 404 Square, Hawassa old central area

• Integration of public plaza with traffic square,

• Conceiving the setting at a national or international level, then the whole

The areas shaded in dark red show the bigger

Classify them in to three hierarchies

• Emergence of administrative class.

• The location of urbanization: urban growth is most noticeable in

1. Population Decline of birth rates; Unbalanced demand for public

Need for new services and

Technology centres and parks;

Efficient public transport in

Growth of high –speed rail , air

6. Environment/ Transport and industry  Cities in fast growing and

Developed by E. Howard (1898) –in the name of ‘Social Cities’.

Later the name is changed to ‘Garden Cities of Tomorrow’.

The model that has practiced in more than 70 countries.

Diagram 1 Diagram 2 Diagram 3

Diagram 4 Diagram 5 Diagram 6

 Intended to bring together the

 Similarity with classical cities.

 Hierarchical arrangement of nodes.

 Space covering hexagons for

 Equi-distant centers with 5

 Services of hexagonal non-

It is part of regional growth theory.

Spot refers to poles/nodes and axis refers to spatial pattern, mainly

Axis acts as channels of polarization and diffusion.

A uniform plain assumption of urban spatial

Growth Poles and their Developments

Growth Poles and their Developments

Public square and space

This is due to the following basic reasons: -