THEORY OF URBAN DESIGN
I. Concept of space
Traditional definitions

Oxford English Dictionary:
Two meanings of space:
1.
Time or duration
2.
Area or extension (more common definition)
In physics, space has three dimensions (x-y-z axes)
and is considered as a volume not an area.
Sir Isaac Newton (17th C) elaborated that space is
absolute….proper to itself…..and independent of the
objects it contains (objects fit into space an d not viceversa)
New Approaches

1.
2.
Two main categories of space exist:
Mental Space (experiential)
Physical Space (existential)
The notion of space is said to originate in an observers
mind and is later imposed as a structure on the
physical world….mental space is an image of physical
space
The concept of space differs from culture to
culture…Different cultures have characteristic spatial
designs as expressed in their cities, buildings, and
art(ref. Dogon villages; japanese Mandala e.t.c)
……but space itself is universal! (transcends culture)
II. THE CONCEPT OF AESTHETICS

Aesthetics in urban design refers to the

Order and beauty in a town are a
necessity, not an after thought…..they are
as much a prerequisite to human health
as is fresh air.
creative arrangement of the elements of a
town in a beautiful and functional manner.
Site-City-Observer Relationships
(viewing city from surrounding and vice-versa)

Extracted form: harmony between buildings and nature….e.g
consider basic slopes, angle of hills, vegetation/tree canopies, and rock outcrops.
Reflects dominant and pervasive features of nature

Vistas and site supremacy: view of landscape from the

Expression: space markers /symbolgy/ ornamentation/detail e.g

Entrance/Approach: profound impact of cities on the visitor who

Colour and light: choice of

Water: proximity to water and possible interplay a natural asset;
city…beautifully framed countryside (panorama)
towers and minarets; landmarks; accent of urban landscape and skyline
traverses long, crowded streets/water.
colour to reflect aesthetic sensibility;
quality of natural light an important visual factor.
water edges, harbours, shorelines, islands, canals e.t.c
 Geometry: form and relationships of angles, lines, curves e.t.c
 Human scale: how each inhabitant would use space and how
they would feel in it.
Aspects of Urban Form
(see BUR 203 notes)
Imageability: Physical Image v/s Functional Image
 Form-Function Relationship
 Main Variations of urban form and
structure: Linear, radial, grid, cluster e.t.c
 Objectives of urban form (includes growth;

Meaning and identity e.t.c)

Growth and decline
Existing Theories and Practice

Theories that have motivated and still inform the
construction of cities are both normative and
functional.

Normative theories attempt to specify

Functional theories attempt to explain how cities
"goodness“….what is good city form?... and
discuss in detail the aspects that create good
cities…..Prescriptive…..What cities ought to be!
perform by concentrating on city form
processes, spatial and social structure, and form
models……Descriptive……What cities are!
Normative Theories
(selected examples)
1. The Cosmic Model

It assertions that the form of a permanent settlement
should be a magical model of the universe and its gods.

Such a crystalline city has all of its parts fused into a
perfectly ordered whole and change is allowed to
happen only in a rhythmically controlled manner

specific phenomena included: such as returning, natural
items, celestial measurement, fixing location,
centeredness, boundary definition, earth images, land
geometry, directionality, place consciousness, and
numerology
2. The Machine Model

The analogy between city and machine has a long
history (ref. Egyptian and classical “per strigas”, Ron Heron’s
insect city; archigram movement; plug-in concept)

it occurs often when there is no long-term goal in mind
but the settlement has to be created hurriedly and its
future growth will be determined by still unforeseen
forces

Its form requires a few simple rules of urbanization and
the outcome is factual, functional and devoid of the
mystery of the universe.

Among its attributes are convenience, speed, flexibility,
legibility, equality, and speculation.
3. The Organic Model

The analogy between city and living organism is fairly
recent arising with the growth of biology in the 18th and
19th centuries (ref. metabolists)

Model is critical of others, especially the machine model
with its "simple grids" as “static”

It asserts that an organism:
- is an autonomous being, with a definite boundary and is of a specific size.
-does not change merely by adding parts but through reorganization as it
reaches limits or thresholds.
- contains differentiated parts but form and function are always linked.
- is homeostatic, self-repairing and regulating toward a dynamic balance.
- undergoes cycles of life and death as is rhythmic passage from one
state to another.
Organic model (cont’d)

From this flows the notion of the form of the organic
city:
- A separate spatial and social unit made up internally
of highly connected places and people.
- A healthy community of heterogeneous and diverse
nature
- The micro unit is the neighborhood, a small residential
area, defined by Clarence Perry in 1929 as the support
area for an elementary school, to which children, the
most vulnerable of the human species, can safely walk.
- Like organisms, settlements are born, grow and
mature, and if further growth is necessary, a new entity
has to be formed. Thus there are states of optimum size,
beyond which pathological conditions ensue.
Organic model (cont’d)
- Greeenbelts not only ensure an intimate contact with
nature but enclose healthy growth.
-A model with typical physical forms, among which radial
patterns, anti-geometrical layouts, and a proclivity for
natural materials.
- Often the organic idea is extended regionally to connect
settlements to valleys, trails and other extended natural
systems.
-There is an attraction to small-scale modes of production
or services as opposed to large-scale synthetic
processes. Often the model aligns itself with a socioeconomic philosophy that sees increases in urban value
as the result of communal rather than individual
endeavor.
4. The Contextual Model

This relates new development to an analysis of existing urban
structure.

A prominent concept of this canon is that of “serial vision” …. the
sequential and unfolding nature of urban experience
(foreground/middle ground/background), ………………with its
corners, divisions/modules, protrusions, and recesses/setbacks e.t.c
creating aspects of interest and surprise.

Context is something that has no clear or common spatial definition;
thus the impact of contextualism will vary with geographical location
and cultural influence.

The mainstream urban design has been strongly influenced by
contextualism in terms of a new respect for the overall form of the
traditional urban street and block and a concern for public realm

(ref:Imageability (Kevin Lynch); permeability (Jane Jacobs); adaptability/robustness
(Standford Anderson). These ideas were later published as Responsive Environments
(Alcock et al)
5. The pragmatic Model


This is whereby urban design is defined according to the
needs of the epoch….. where the tools and concepts are
used selectively and exclusively in regard to the locality.
The danger with this model lies in:
-Likely loss of understanding of the larger processes
affecting urban form
- Possible inability of making informed decisions at urban
scales
- Failure to embrace environmental disciplines that are
currently excluded and isolated from mainstream urban
design.
6. The Constructivist model

This explores techniques of form to create urban interventions that
express the spatial and temporal complexity of a given age.

“Deconstructionists” are constructivists who use unconventional

Ref.
techniques of form to express the essential fragmentation in city
environments.
Peter Eisenman applies an approach that is more mathematical and rational
in nature, which tends to reject any hint of historical contextualism.
Rem Koolhaas makes free use of the typologies of modernism, recombining
them in new and ironic ways
Bernard Tschumi, exploits the random collisions that results from the
layering of unrelated activity frameworks.
Frank Ghery and Zaha Hadid use unconventional techniques of form to
express order among chaos of modern cities
7. Functionalist Model

This was dedicated to exploring new
interwoven urban structures that would allow
opportunities for social encounter/contact and
exchange whose end result is a humanising
influence.

The interpretation of this philosophy,
however, varied widely in practice: low-, medium-,
and high- density; vehicular and pedestrian segregation e.t.c

( Ref:Aldo van Eyck, Ralph erskine, Giancarlo De Carlo)
8. Rationalist Model

This offered a morphological/structural approach to urban design
that related new urban development to the historical structure of
the city and typologies of urban space.

The figure-ground drawing was widely used as a design tool.

As “critical reconstruction”, this method was used to maintain and
restore the traditional 19th century street pattern and form of the
urban block, street and square, without constraining the
contemporary architectural expression of new building additions.

This was not a plea for unthinking preservation or for regarding the
city as a museum; rather, the aim was to explore the deep structure
inherent in building types and how built forms accommodate
changing, living uses over time.

(ref. Robert Venturi, Aldo Rossi, Scott Brown, Colin Rowe, Rob & Leon
Krier)
Functional DescriptiveTheories
These are founded on the following characteristics:
 Urban history: the city is regarded as a unique historic process...
explaining cities as derivative of their own culture (ref Sjoberg, Rapoport).

Urban Ecology: city is regarded as an ecology of people, each
social group occupying space according to economic position and
class. (Ref. Burgess [concentric model], Weber, Simmel and
Spengler)

City economy: regards the city as an economic engine in which
space, unlike in the previous category, is both a resource and an
additional cost imposed on the economy for production or
consumption….location of cities an optimization of raw materials,
labour and market locations (ref. Isard,Von Thunen,Christaller)
Functional Descriptive Theories (cont’d)


Urban Communication: regards the city as a field of forces, a
communications network of particles which attract and repel each
other much as they do in physics.
Sub-sets of these ideas include population potential maps, gravity
models, communications flows, and various topological models.

Urban Politics/Governance: understanding the city as a system of
linked decisions...affluence, imminent domain, citizen participation
in a democratic city; the game theory, in which people interact
together according to fixed rules and produce agreed-upon
outcomes

Urban Chaos: rejects previous theories of competition and posits the
city as an arena of conflict, in which the city's form is the residue
and sign of struggle, and also something which is shaped and used
to wage it. (Castells, Harvey. Lefebvre, Gordon)
Design Principles and Techniques

Together these help in the correlation and
synthesis of spaces, functions, circulation, sites,
and orientation…

Their choice and application (singly or
combined) will depend on the problem context
(modus operandi)

Overall they facilitate the conceptualizing
process…..entailing decisions and choices
1. Design Principles
i)
Scale: refers to any system of measurement
appropriate to the context. Proportion as an aspect of
measurement introduces the aspect of
relativity…between two objects…the measured and a
universally known object…e.g headroom describes
space relative to human height.
A module is one part of a system of relative
proportions, where one part can combine with other
parts to form a larger object
(ref. Le corbusier’s Modulor)
Applications of Scale in urban
design


Scale and Human vision: our eyse have two fields of
view – general and detailed. General cone of vision 30
deg up; 45 deg down; 65 deg to either side.
The above determines urban scale in several ways: we
cannot see an object that is further from us than 3500
times its size…8 feet is normal conversation distance; a
person between 3 and 10 ft is in close relationship to
us…use of normal voices; we can pick facial details up to
about 75ft. Beyond this, there is need to complement
with gestures…up to about 450ft…also maximum for
distinguishing man from woman…maximum viewing
distance for human figures is around 4000ft.
Scale and circulation: scale is determined by
the means we employ for movement around the
city as well as the way we move between cities
across the country.
Scale is determined by the different modes of
movement based on their speeds and sizes, but
also characteristics in movement…express
versus stop-over/interactive…
Scale and neighbourhood size: The citizen
numbers and levels of services will determine
the scale of a neighbourhood…the scale of a
network of neighbourhoods would determine the
scale of the entire town.

Scale in neighbouring buildings and
spaces:
Buildings and spaces have to be in scale with
people, as well as in scale with each other….this
will also apply to other variables like materials,
colour, bulk, and siting.
Intentional variations in scale could be used to
achieve emphasis and hierarchy in design of
buildings and spaces
 Scale and parameters: This is where we use
attributes of familiar and known objects and
details such as cars, trees, humans, light poles
e.t.c to judge the sizes of other things near
them

Scale versus Age, time, convenience and habit:
Our sense of urban scale varies with our ages and
habits….the world of a child begins with the home…as
one grows the world enlarges and separate parts are
linked together…the scale of their world enlarges
Our sense of urban scale is also determined by what we
are accustomed to…people adapt to environments with
time…say getting used to the skyscrapers around us.
Urban scale may also vary with the temporal cycles of
the city…the rush hour with its fast traffic has a different
view of scale to the sluggish period of the day, when
people have all the time to observe and pick details
about the city.
ii) Urban Space: may be isolated or linked; may
be purposely designed to display linkage or to
emphasize buildings and objects they contain.
Space may be linear/corridors; squares; or
reserves…based on their sizes they define the
hierarchy of spatial types…..from small intimate
sizes to urban squares and the natural space
within which the city is set.
Spaces may also be enclosed or open….45 deg
is full enclosure; 30deg is optimal; 18 deg is
minimum…anything less is lack of it!
iii) Urban Mass; This refers to the arrangement of ground
surface, buildings, and objects to influence the quality of
urban space and to shape urban activity patterns on
both large and small scales.
In terms of massing, buildings may be projecting into
space, be on a space, or in a space.
Our vision and light conditions govern the way we perceive
masses…
Vision: 45deg is for details; 30deg is for whole objects;
18deg is for object plus context
Light: under bright, clear sunlight the individual parts of
objects will tend to stand out…..as light subdues we tend
to see less of details and more of the overall object.
Sculptured objects are best viewed under even light such
as shadow light…thus northern and southern facades
may transmit details differently…..depending our position
in relation to solar patterns.
iv) Responsiveness; these could be sensual or
environmental

Sensual: attempt to cater for all the senses:
Visual,Tactile, Auditory, Olfactory, Kinaesthetic

Environmental; that which provides users with
essentially democratic settings and enrich their
opportunities by maximising the degree of choice
available to them; the available techniques include:
i) Permeability
This refers to the number of alternative routes
through an environment; it affects where people can
go and where they cannot. This offers choice through
accessibility and must be considered at early stages
of design.
ii) Variety
This refers to the range of uses availed to
people in a given environment; it is the
experience of a degree of choice provided by
intermix of uses
iii) Legibility
This refers to the ease with which people can
understand the layout of a given environment
and the kind of opportunities it offers.
iv) Robustness
This refers to the degree to which an
environment can be used for different purposes
as opposed to those with a single fixed use.
v) Visual appropriateness
This refers to the detailed appearance of a place that
makes people aware of the possible uses; it affects the
interpretations people put on places.
vi) Richness
This refers to the degree of choice in sensory
experiences that a place offers to its users.
vii) Personalisation
This refers to the extent to which people can put their
own stamp on a place; decisions about forms and
materials of the scheme must be carefully made to
support personalization but also protect public role.
Other techniques

Open space technique: where to build versus
where to keep open; a variety of uses…parks,
watersheds, public transit lines, airports, e.t.c
An open space structure would be the framework
for relating land development to transportation
and also allow for other decisions related to
community life: schools, churches, playfields
e.t.c.

Transportation system technique; patterns

Plug-in Technique; where a modular system
of movement as primary land shapers;
morphology of networks against that of the land
parcels they define….density of development
versus intensity of circulation. Varios levels of
network, their hierarchic connectivity, as well as
terminal facilities.
such as that of a grid is created and within these
defined uses and objects can be “inserted” and
removed with ease (flexibility)…initially used as
a technique for design of functions in individual
buildings but later replicated in city-wide design
Theory Versus Practice
(Why urban design matters)
 We design spaces to attract people (public realm)
Urban design creates a framework for our lives.
 understanding how humans perceive the
physical scale and form of cities is essential to
mastering design.


We feel and experience urban design every day

Every road width and building height delivers a message
to their users on how to use the public realm

Design brings order and relation into human
surroundings

Different designs affect residents in different ways, and
make the city’s image more vivid and memorable

Embedded in urban design theories is the
fundamental goal of balancing private
development and public good in a way that
incorporates the social, economic, and cultural
needs of a diverse urban population

Urban design must solve practical problems of
functionality first and foremost, as it creates tools for
people and their quality of life.