Transcript Lecture 7 - Department of Urban And Regional Planning

URBAN ANALYSIS
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This refers to a process of rationalizing urban
planning and design by investigating the form of
urban areas, theories of city structure, and location
as factors in urban development.
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It entails investigation of basic urban frameworks,
and concepts and tools for analysing and
understanding urban problems.
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The scope of problems investigated may include:
economics (macro and micro) and urban sociology.
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Urban analysis may apply the following
methods/data sources:
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land use and density mapping;
data gathering survey methods;
geographic information systems;
journal/library sources.
Urban analysis is interested in a complex and multilayered understanding of the city…
by building a conceptual framework that
acknowledges that multiplicity through different
pathways to sustainable development. These
pathways often co-exist and function concurrently
within a single city.
Key Issues and Responses in
Urban Analysis
Urban Patterns/trends and their implications
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Zoning and the need for proximity
Mobility/migration
Compaction and the need for variety/richness of a place
Suburbanization and the issue of urban sprawl
Problems triggered by urban forms
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Unsustainable levels of resource use
Inequitable lifestyles
Ecological footprints: the catchment/amount of land
necessarily affected to enable everyday life of a city; the
nature & extent of effects of cities on land/environment.
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The concept of “Environmental Space”
– a measure of the share of resources
consumed by a city in a region or a
country……
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a basis of calculating allowances for
consumption and emissions
(ref. Global environmental space calculation)
The key responses :
1. Shift from singular to multiple models of a
sustainable city
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Questions the over-reliance and emphasis on compact city model
as a universal approach to achieving sustainability.
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Could constrain and blind efforts by researchers and policy-makers
in searching sustainable urban futures.
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Variety in choice of urban form based on local
situations….”MultipliCity”: a variety of approaches considered to
suit particular settlement types….of different scales and locations.
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Consider alternative scenarios and incremental change as opposed
to New Towns approach/wholesome change….consider constraints
of space, cost, and acceptability.
(ref. to pros and cons of the compact city model)
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Rejection of simplistic use of models, instead
develop competing pathways to sustainable cities
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Models not to be used as straightforward deterministic blue-prints
to be translated into reality through physical planning and design
policies in a series of linear stages
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Models to be used in a much softer, more flexible fashion:
conceptual not specific; to sensitize on different visions to a
sustainable city
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Models to consider views and strategies of different urban actors
with competing social, political, and commercial interests.
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Actors views and strategies may resonate or dissonate with the
visions of particular models of development
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Need to understand how the changing social organization of urban
development may promote particular pathways towards distinct
urban futures.
3. Co-existence of diverse sustainable urban futures
within a single city
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charting the multiplicity of pathways towards different
sustainable urban futures
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Examination of tensions and similarities between
pathways: different social assumptions and biases
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Broadening the range of determining factors of
sustainability of urban form: travel & fuel consumption;
effects on ecology, wildlife, and natural resources;
effects on social conditions and well-being e.t.c
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Adoption of inclusive approaches to avoid “islands” of
success stories amid “seas” of failures.
4. Strengthening morphological studies
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Address size, mix of uses, block structures
e.t.c
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Explore different scales of urban form –
from the dwelling to neighbourhood, zone,
district, city, and region
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Determine the key tangible and practical
impacts of theoretical models…achievable
in real terms.
Urban analysis will herein be addressed
under four components:
Urban form - Structure Analysis
 Character Analysis
 Spatial Analysis
 Socio-spatial analysis
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Urban Form – Structure Analysis
There are various classifications on this
subject but generally all taxonomies touch
on key issues:
 urban
space efficiency;
 typologies of built form;
 transport and infrastructure efficiency;
 environmental efficiency;
 socio-economic and cultural considerations.
Human Needs-Based criteria for Sustainable
Urban Form
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Need
Defining characteristics
Provision
for all
physical
needs
Place to live and work; reasonable
income; education and training;
training (mobility) and communication;
access to services and facilities
Human Needs-Based criteria for Sustainable
Urban Form
Need
2
Defining characteristics
Safety, security
and protection
Visually and functionally
ordered and controlled
environment; a place
free of pollution and
noise; a place free of
accidents and crime
Human Needs-Based criteria for Sustainable
Urban Form
Need
3
Defining characteristics
A conducive
social
environment
Place where people
have their roots and
children have friends;
sense of community
and belonging
Human Needs-Based criteria for Sustainable
Urban Form
Need
4
Defining characteristics
Good image,
reputation and
prestige
A place with a Sense of
confidence and
strength; a place with
status and dignity;
opportunities for
individuals to shape
their personal space
Human Needs-Based criteria for Sustainable
Urban Form
Need
5
Defining characteristics
A chance to be
creative
Opportunities for
communities to shape
their own
neighbourhoods
Human Needs-Based criteria for Sustainable
Urban Form
Need
6
Defining characteristics
Aesthetically
pleasing
environment
A place that is well
designed (aesthetically
pleasing); a place that is
physically imageable; a
city that is a place of
culture and work of art
Various models of urban form:
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This looks at the alternative shapes and
structures of cities that could guide desired
(sustainable) development. Analysis of urban
form can broadly be divided into macro and
micro scales.
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Macro-Urban Forms:
The emphasis has mainly been on functional
qualities that depend on overall form and
development pattern of the city;
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Macro-urban forms (cont’d)
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They will address at a larger scale:
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different typologies of housing forms;
good environmental conditions;
access to open spaces for recreation and other functions;
adaptability to changing needs and socio-economic conditions;
access to country-side.
To classify city forms on the above accounts will require
accurate data on:
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overall densities
total area required
minimum and maximum distances, e.t.c
The data is generated using different theoretical city
models e.g input-output model. Evaluation of models is
done based on criteria, standards, and performance
values.
The key macro-urban forms :
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Dispersed City: portrays continued low-density suburban
development of population, housing, and jobs; infrastructure
investment dominated by road development. Encourages urban
sprawl and loss of prime agricultural and countryside land.
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Compact City: portrays increased population and density of
an inner group of suburbs, with associated investment in
public transport
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Edge City: portrays increased population, housing densities,
and employment at selected nodes within the city; increased
investment in orbital freeways linking the edge cities.
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Corridor City: focuses growth along linear corridord emanating
from the central business district (CBD), supported by upgraded
public transport infrastructure
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Fringe City: arises from additional growth predominantly on the
fringe of the city.
The above macro-forms translate into various identifiable
geometries; these include:
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The core city/urban core
The Star city/radial city
The satellite city/Stellar pattern
the Urban galaxy
the Linear City
the Polycentric City
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(ref. BUR 202 notes for definitions, merits and demerits of each of the above)
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Micro-urban forms:
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These are based on interrelationship of people,
transport and amenities; they address the
degree of user-friendliness in terms of mobility
and access to services and facilities within
walking and cycling distance and by public
transport.
Micro-urban forms cover a number of component
areas:
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Various neighbourhood types, including digital
Sustainable neighbourhoods, as envisioned in the
Urban Villages Movement, seek to rediscover the
balance between housing growth with the
development of a strong and broad-based local
economy. The main features include:
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The main features of sustainable neighborhoods
include:
A vibrant mix of uses: working areas; higher
density housing; predominantly residential areas
A hierarchy of open spaces: neighbourhood
central square; pocket play parks; toddlers’
greens; riparian/canal corridors
Integrated transport system: main
bus/tram/light rail route; local bus route;
neighbourhood street; local distributors; access
roads
Local facilities: shops; primary schools; places
of worship; community facilities
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Various types of neighbourhoods include:
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Inner urban neighbourhoods: older suburbs with older
housing stock, mostly done by local authorities
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Modern Suburbs: usually of mixed high- and low- rise
development mostly undertaken by private
developers/building societies or housing authorities e.g
NHC.
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Urban Extensions: new neighbourhood areas currently
planned on the edges of existing built-up areas.
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Brownfield Sites: Large sites of at least 20hectares in a
single ownership where the building structures have
been identified for clearing to pave way for new
neighbourhood development. Mostly where the original
use has ceased e.g disused railway yards.
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Digital villages address the needs of the society while
taking advantage of advancement in Information and
communication technologies (ICT)
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Neighbourhood Structure studies often address the
following:
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Neighbourhood unit structure – overall, generalisation of key
features
Neighbourhood pattern e.g transit system; home-work
distribution
Neighbourhood Elements:
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Street pattern types
Block types
Infrastructure types: lot scale; block scale; neighbourhood scale
Frontage types
Building types
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Transects
A transect is a system of classification deploying
the rural-to-urban continuum to arrange in useful
order the typical elements of urbanism.
The elements may broadly be classified
hierarchically as falling under:
Urban core; urban centre; general urban; suburban;
rural reserve; and rural preserve.
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Clusters: These are agglomerations of
neighbourhoods integrated by shared infrastructure
and amenities e.g public transport system; together
they could form a regional urban centre. Cluster
model favours high density areas.
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Townscape and city image
Townscape refers to the collective view of the relationship
of the elements that create the town environment:
buildings, trees, cars, water, traffic, squares,
advertisement and signage e.t.c…
it is about optics, about places, and about content and
their weaving to create the overall town image.
Townscape is about underlying visual relationships that
evoke a broad range of human response.
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Image of the city is the mental picture a person
constructs of the parts of a town based on physical
relationship between those parts….it a collective picture
of what people extract from the physical reality of the
town. …expressed in form of an “impression map” or “image map”.
Use is made of basic elements as conceptualised by Kevin Lynch:
path, edge, node, district, landmark (ref. BUR 202 notes)
Performance evaluation criteria for urban
form & structure
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Degree of containment of development
Population density relative to land needed
Viability of public transport
Dispersal of vehicular traffic
Viability of mixed uses
Access to facilities and services
Access to green open spaces
Environmental conditions 9noise, pollution, congestion)
Potential for local autonomy
Potential for self sufficiency
Degree of adaptability
Imageability of the city (physical entity) as a whole
Imageability of parts of the city (neighbourhoods, districts,
towns)
Sense of place and centrality