Structure of Urban Areas

8/3/2019 Structure of Urban Areas

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STRUCTURE OF URBAN AREAS,DENSITY PATTERNS


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Defining the urban areas:-

Municipalities ,corporations, cantonments areautomatically treated as urban areas

The villages satisfying the following criteria are alsotreated as urban areas:

A minimum expected population 5000

Population density of 400 persons per square KM

At least 75% of male working population should beengaged in non agricultural pursuits.


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URBAN PATTERNS:-

These are mainly of 4 types:-

1.Gridiron plan or the chessboard plan

2. The radial plan

3. The spider web plan

4. The irregular plan


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THE GRID IRON PLAN: the plan of all ages is almost asimple rectangle divided up into square blocks for building

streets intersecting at right angles. this has been termedthe grid iron or the chess board plan.

The first planned Greek city was probably Miletus,which was rebuilt to a grid plan after 479 BC. Its griddeddesign has been credited to Hippodamus Miletvesof ancient Greece the grid plan iscalled Hippodamianplan.


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The grid plan dates from antiquity and originated inmultiple cultures some of the earliest planned cities werebuilt using grid plans, the citieswere built with blocks

divided by a grid of straight streets, laid out in perfectright angles, running north-south and east-west. Eachblock was subdivided by small lanes.

Ancient towns like Memphis , Thebes , urs , Babylon ,PersepolisMohenjo-Daro , Peking emerged in the ancient period inthe fertile valleys of Egypt , Mesopotamia , India andchina.

Later on, Greek and roman towns like Athens , Miletus ,Priene , Syracuse, Rome, etc.., were founded and later with

the colonial expansion of roman empire , Baalbek ,Lebanon , Timgad and many other towns came into


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With the era of renaissance , there took some changes inexisting cities.

In the renaissance city plans, the basic concept wasforming straight streets. Chess board pattern of streetlayouts was adopted to create gardens and fountains withnew types of public squares.

Florence , Milan and Vienna in Europe and Jaipur in India

are the examples of these type

Newly build cities in India like, Chandigarh ,Gandhinagar , are also on the same pattern.


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The tradition of grid plans is continuous in china from the 15thcentury BC onward. Guidelines are :

"a capital city should be square on plan. Three gates on eachside of the perimeter lead into the nine main streets that crisscrossthe city and define its grid-pattern.

And for its layout the city should have the Royal Court situated in

the south,

the Marketplace in the north,

the Imperial Ancestral Temple in the east

the Altar to the Gods of Land and Grain in the west."


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THE RADIAL PLAN: towns , thus established at theroad junctions, took the form of a radiation plan. Thehouses in such a plan simply straggle out in ribbons

along the roads.


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Cities of America , like Washington, D.C and NewYork have radial plans

Cities like Indianapolis and Madison are diagonallyplanned. Both the cities were based upon the gridiron,but diagonals ranged from the center to the four

corners of the plan


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SPIDER WEB: for a better administrative control a seriesof circumferential road are introduced on radial plan

which also gives controlled development. It is termed asa spider web plan.


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THE IRREGULAR PLAN: some times it becomes very difficultto remold to certain natural features (like streams, lakes,

rocks) according to the need of the prepared plan. In suchcases distances are long and extra land has to be acquired.

Small walled town :noerdlingen in germany


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DENSITY PATTERNS:-

Densities are mainly of three kinds.

:- NET DENSITY

:-GROSS DENSITY

:-OVERALL DENSITY


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OVERALL DENSITY:- which means the number of people peracre over a large area of the town, affecting its general

economy.

There is yet another kind of density called towndensity which means the number of people per acre overthe entire area of the town, embracing residential,

industrial, commercial, educational, recreational, transport

NET DENSITY:- net density means the no of people peracre of the residential area including small gardenpatches, open spaces between buildings , internal roadsand half the width of surrounding roads up to 20 feet.

GROSS DENSITY:- gross density means the no of peopleper acre over the whole of defined areas which includespublic buildings , industrial buildings and large spaces

and half the width of the surrounding roads.


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4/29/12Diagrams showing land used by the dwellings, shopsschools and o en s aces for 1000 eo le at net ross and


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This is the general densitypattern in India


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This is the general densitypattern in brazil


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THANK

Structure of Urban Areas

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