Architectural
design begins with the preparation of a building program and site analysis. So,
too, do plans for designing or redesigning a portion of a city, In the case of
a city, the analysis is a diagnosis of the city’s component pieces, to see the
relations between these pieces and to assess their condition, A visual surveyin
urban design is an examination of the form, appearance, and composition of a
city—an evaluation of its assets and liabilities. A visual survey also enables
the urban designer to see where the city needs reshaping.
Key
words
actvity, density,
district, image, route, scale, skyline, traffic pattern,
urban structure,
visual survey, vocabulary of urban form
Credits:
This article is a chapter of the author’s writings, Urban
Design, published by the American Institute of Architects and McGraw-Hill,
1965, and first appeared in AIA
Journal,S 1964. Drawings are by the author.
Making
a visual survey
A Working Vocabulary of Urban
Form
Architectural
design begins with the preparation of a building program and site analysis. So,
too, do plans for designing or redesigning a portion of a city. In the case of
a city, the analysis is a diagnosis of the city’s component pieces, to see the
relations between these pieces and to assess their condition. A visual survey
in urban design is an examination of the form, appearance, and composition of a
city—an evaluation of its assets and liabilities. A visual survey also enables
us to see where the city needs reshaping.
A
visual survey can be made of any city or town, regardless of size. It can also
be made at different scales—a neighborhood, the center, a suburban area, or a
small group of buildings. Furthermore, it can be made for a built-up part of
the city which is going to be altered very slightly or for a part of the city
which is going to be
rebuilt
entirely. The process of making a visual survey is not complicated, nor need it
be done with a high degree of precision. As a matter of fact, it is best done
in general terms, for to deal with the city on a large scale we must think
broadly.
To
conduct a visual survey, one must have a basic idea of the elements of urban
form. These necessitate a descriptive vocabulary.
The
Image of the City.
People’s impressions of
a building, a particular environment, or a whole city, are, of course, more than
visual. Within the city lie many connotations, memories, experiences, smells,
hopes, crowds, places, buildings, the drama of life and death, affecting each
person according to his particular predilections. From his environment each
person constructs his own mental picture of the parts of the city in physical
relationship to one another. The most essential parts of an individual’s mental
image, or map, overlap and complement those of his fellows. Hence we can assume
a collective image-map or impressions-map of a city: a collective picture of
what people extract from the physical reality of a city. That extracted picture
is the image of the city.
Every work of
architecture affects the details and often the whole of the collective image.
The collective mental picture—the image of the city—is largely formed by many
works of architecture seen in concert or in chaos, but definitely seen
together.
Several years ago,
Prof. Kevin Lynch conducted a study of what people mentally extract from the
physical reality of a city. He reported the results in a book called The Image
of the City, and his findings are a major contribution to understanding urban
form and to architecture as component parts of that form. Professor Lynch is one
of the country’s leading investigators of urban form. Many of the ideas in this
book were derived from his studies. In his examination of the form of the city,
Professor Lynch found that there are five basic elements which people use to
construct their mental image of a city:
Pathways: These are the
major and minor routes of circulation which people use to move about. A city
has a network of major routes and a neighborhood network of minor routes. A building
has several main routes which people use to get to it and from it. An urban
highway network is a network of pathways for a whole city. The footpaths of a
college campus are pathways for the campus.
Districts: A
city is composed of component neighborhoods or districts; its center, uptown,
midtown, its in-town residential areas, trainyards, factory areas, suburbs,
college campuses, etc. Sometimes they are distinct in form and extent—like the
Wall Street area of Manhattan. Sometimes they are considerably mixed in character
and do not have distinct limits—like the midtown area of Manhattan.
Edges:
The termination of a district is its edge. Some districts have no distinct
edges at all but gradually taper off and blend into another district. When two
districts are joined at an edge they form a seam. Fifth Avenue is an eastern
edge for Central Park. A narrow park may be a joining seam for two urban
neighborhoods.
Landmarks:
The prominent visual features of the city are its landmarks.
Some
landmarks are very large and are seen at great distances, like the Empire State
Building or a radio mast. Some landmarks are very small and can only be seen
close up, like a street clock, a fountain, or a small statue in a park. Landmarks
are an important element of urban form because they help people to orient
themselves in the city and help identify an area. A good landmark is a distinct
but harmonious element in its urban setting.
Nodes:
A node is a center of activity. Actually it is a type of landmark but is
distinguished from a landmark by virtue of its active function. Where a
landmark is a distinct visual object, a node is a distinct hub of activity.
Times Square in New York City is both a landmark and a node.
These
five elements of urban form alone are sufficient to make a useful visual survey
of the form of a city. Their importance lies in the fact that people think of a
city’s form in terms of these basic elements. To test them, sketch a map of
your own city, or better still, ask someone else to do it, taking only a few
minutes. The result will be two fold: a picture of the most salient features of
a city’s form—its image—and a map of the sketcher’s particular interests as
they relate to the city. The result will also be akin to the cartoon maps of
the United States as seen through the eyes of a Texan or a New Yorker. The
features will be distorted and probably exaggerated, the degree of distortion
reflecting the hierarchy of values of the sketcher. The more “imageable” a city,
the easier it is to find one’s way about in it, even if its street pattern is
not clear. In designing a city, it is important to consider how a new
development will affect the total urban image. A new development can be made to
tie visibly into a city’s path system; to form or help reinforce a district; if
on an edge, to strengthen the edge; and if at a seam, to maintain continuity.
It can also become a good landmark and an active node.
Paths,
landmarks, nodes, districts, and edges are the skeletal elements of a city
form. Upon that basic framework hangs a tapestry of embellishing
characteristics which all together constitute the personality of a city. To
build a broader vocabulary upon this basic framework we must consider landform,
natural verdure, climate, several aspects of urban form itself, certain details
and several lesser facets of form.
Landform
and Nature
Every
city is built on a piece of land. The form of this land and its features are
the foremost determinants of a city’s form. In speaking of landform, we are
speaking primarily of topography.
In
looking at landscape, we are seeking its character. As urban designers we
observe the form of the terrain—flat, gently rolling, hilly, mountainous—in
relation to the architecture and the cities which are set in it. A flat site
may suggest either vertical architecture or assertive horizontals. A slightly
hilly site may call for vertical architecture at the summits with a flow of
cubes on the slopes, or may suggest a termination of architecture just below the
crests. A steep hillside or valley may lend itself to terracing, with
orientation to the sun. In every case we must assess the qualities of the
terrain, including the design relationships they express. The prominent
features of a landscape should be carefully noted— cliffs, mountain peaks,
ranges of hills on the horizon, plateaus, rivers, or lakes. These are accenting
landscape features which can be employed actively as sites or passively as
vistas, supplementing architectural and urban form. They can be used as major
vista objectives from points within the city or as special sites for buildings.
Some are better
left in their natural state.
Indigenous
greenery should be assessed in terms of shape, size, character, practicability,
and seasonal change. An urban designer needs a working knowledge of the local
flora and its suitability in various uses. A thickly foliated tree, formally
shaped, might be proper for lining a road to shield the automobilist from a low
sun. A spreading shade tree of informal shape, might be quite appropriate as a restful
sitting place in the bustle of the city.
Characteristic
detail of the landscape should be considered for possible use as architectural
and urban design embellishment: a native rock or gravel, a characteristic earth
color, the form of local streams, characteristic stands of trees. Indigenous
architecture should also be noted, particularly in older towns. These are the
result of evolution and may have achieved a mature relationship with their environment.
Certain
areas of landscape should not be touched, but preserved in their natural state.
A survey of the natural landscape may disclose areas which are better left as
wilderness. These might well be chosen with relation to nearby cities and towns
so that they are accessible as necessary complements to urban life, but not
menaced by it. Buildings and small towns can often be seen in their entirety in
the framework of nature. As such, they are accents or counterpoints to their
natural settings, elements of vitality in a setting of repose. A larger town,
however, can seldom be seen in its entirety, but only in part, from various
viewing places. Here we have a one-to-one relationship, nature being less a
setting than a major component of the whole scene—balancing the sight of the
city rather than acting as a setting for it. Raw nature sometimes exists within
large cities in the form of streams, rivers, shore lines, cliffs, etc. Here the
city is the setting for nature. Nature, in this circumstance, becomes a foil or
counterpoint to the urban surroundings.
Thus,
we might regard a small town as an object in the embrace of nature, a larger
town as being hand-in-hand with nature, and finally, the large city as assuming
the role of nature and becoming the embracer.
A
visual survey of nature in relation to achitecture and urban design is
threefold in scope. We first try to determine the character of the surrounding
landscape to which our architectural and urban forms must respond esthetically
and functionally. Second, we evaluate the degree to which our existing
architecture and cities enhance nature.
Third,
we must decide what natural areas are to be left alone to act as complements to
urban form. Throughout this process we search for assets and liabilities,
preserving and enlarging upon the one and noting corrections to be made on the
other.
Every
work of architecture affects the natural landscape either positively or
negatively; so does every structure and human settlement. Nature, in turn, as a
setting for our constructions, is a visual framework to which all our
constructions must respond.
Local
Climate
While
on the subject of the natural features of the terrain, it is wise to check on
local climatological conditions. Local climate determines much of the character
and appearance of the landscape and buildings.
The
following aspects of climate can be readily found in United States Weather
Bureau publications. Temperature: Seasonal temperature and humidity as averages
and extremes which indicate the periods of relative comfort, the extremes which
must be ameliorated, and which therefore determine architectural and urban
form.
Light:
The number of clear, partly cloudy, and fully cloudy days, which conditions the
light affecting the appearance of the city and of buildings.
Precipitation:
The amount of precipitation in the form of rain and snow.
Sun: The
angles of the sun in different seasons, which affects viewing conditions and,
thus, design. It is useful to make a simple three-dimensional model to study
these angles.
Winds:
The prevailing seasonal winds including the direction and intensity of cold
winter winds, gentle or severe fall and spring gusts, and cooling summer
breezes. These affect design considerably.
In
addition to these quantitative factors there are a number of qualitative
aspects of climate which are as important in urban design. Some cities are well
oriented toward the rising sun or the setting sun. Some cities have forms that
derive almost directly from their climates— arcaded cities in the sun, for
example, Considerable research or experimentation might be done to determine
how cold winter winds could be slackened and cooling summer breezes induced.
The quality of light—sharp and clear or cloudy and dull—should be a determinant
in the design of building facades including their degree of intricacy and their
coloring. These are always a matter of artistic consideration but a careful
appraisal of actual conditions can help a decision.
Shape
Every
city has a general overall shape. There are several classifications of shape.
Radiocentric:
The most frequently found urban form is the radiocentric, a large circle with
radial corridors of intense development emanating from the center.
Rectilinear:
A variation on radiocentric form is the rectangle, which usually has two
corridors of intense development crossing at the center. This variant of the
radiocentric form is found in small cities rather than large. It is the
radiocentric form with right angles.
Star:
A star shape is a radiocentric form with open spaces between the outreaching
corridors of development.
Ring:
A ring shape is a city built around a large open space. The San Francisco Bay
is such an open space for the cities of the bay area. A ring and star may be
found in combination, particularly where a loop road is built around the
outskirts of an expanding metropolis.
Linear:
The linear shape is usually the result of natural topography which restricts
growth or the result of a transportation spine. Stalingrad in the Soviet Union
was planned as a linear city. The megalopolis on the East Coast has become a
vast metropolitan area with a linear configuration.
Branch:
The branch form is a linear spine with connecting arms.
Sheet:
A vast urban area with little or no articulation. Articulated Sheet: The
articulated sheet form is accented by one or more central clusters and several
subclusters.
Constellation:
The constellation is a series of nearly equal-size cities in close proximity.
Satellite:
The satellite is a constellation of cities around a main center.
These
classifications of form have definite implications for a city’s function. They
have advantages and disadvantages related to circulation, proximity to open
space, and articulation of neighborhoods or districts. Further, these
classifications may be applied to the city as a whole or to parts of the city,
isolated for study, like open spaces or circulation. The open spaces of a city
may be linear or branched; or they may form a radiocentric pattern. The
circulation networks may likewise be described as one or another shape.
Size
and Density
Closely
related to a city’s shape is its size, a quantitative aspect which can be
approached several ways. We first of all think of the physical extent of a
city: so many miles across or so many miles from center to outskirts. We can
also describe size in terms of the number of inhabitants. The relation between
size and density is important, for it indicates the distribution of people and
the city’s urban massing.
Density
can be computed mathematically in several ways: the number of people per square
mile; the number of houses per acre or square mile; or the amount of building
floor area in a given section. It can also be expressed in terms of automobile
population. In 1962 Los Angeles, the country’s most auto-oriented city, had
2,220 cars per square mile and Washington, D.C., had 4,100 cars per square mile.
This comes as a surprise to most people. One would think that those figures are
reversed—which suggests a note of caution in judging aspects of quality from
statistics of quantity. The gross size of a city in terms of its population is
also revealing.
Classifications
according to size alone are quite useful. A basic population of about 200,000
to 300,000 is necessary to support basic public cultural facilities. Amsterdam,
Holland, with a population of about a million people, is of the maximum size
that can be traversed on foot by a hearty walker, from center to outskirts. Unless
a city is evenly built-up, studies of density are best made on separate sectors
of a city. Density figures indicate the relationship between built-up and open
land; therefore they can describe almost graphically the image of a suburban
residential area or an in-town row-house area. Densities have definite
implications for various forms of transportation. In making a visual survey, it
is helpful to determine the density of various areas and to relate the density
figures to physical patterns of land and buildings and, hence, the visible
form
of the area.
Pattern,
Grain, and Texture
Urban
areas have distinct patterns. Usually these are seen in their block and street
layouts. Most American cities have rectilinear block and street patterns. On
rolling terrain, in outlying areas, curvilinear streets and blocks form another
type of pattern. A cul-de-sac system forms a third pattern. Mixtures of open
space and built-up space constitute still another pattern. A basic design
pattern can be very helpful in planning a residential area or a campus area. An
urban pattern is the geometry, regular or irregular, formed by routes, open spaces,
and buildings.
Grain
is the degree of fineness or coarseness in an urban area.
Texture
is the degree of mixture of fine and coarse elements. A suburban area with
small houses on small plots has a fine grain and a uniform texture. With small
houses on varying size lots, it could still have a fine grain but an uneven
texture. In the city, large blocks with buildings of varying sizes could be
described as having a coarse and an uneven texture. If the buildings are
uniform in size, they could be described as having a coarse grain but a uniform
texture.
Such
distinctions are easily indicated on a sketch map. They are useful in
evaluating an area’s form and in making decisions about a design treatment for
it. For example, a coarse-grained unevenly textured area may be impersonal and
repellent and could be treated with some fine scale and unifying design
elements, An extensive and uniformly-grained area might well be treated with
relieving accents.
Urban
Spaces and Open Spaces
Urban shape, pattern, grain, size, density, and texture are primarily aspects of solid form—the building masses of the city, In architecture it is rather helpful to conceive of a building not only as a solid but as spaces modeled by solids. It is also helpful to consider a city this way. The spaces of the city range from the space of the street to the space of a park system and, ultimately, to the vast space in which an entire city exists. It is helpful to think of these spaces as two generic types: formal or “urban spaces,” usually molded by building facades and the city’s floor; and natural or “open spaces,” which represent nature brought into, and around, the city.
Basically
an urban space must be distinguished by a predominant characteristic, such as
the quality of its enclosure, the quality of its detailed treatment or
outfittings, and the activity that occurs in it. An urban space should,
ideally, be enclosed by surrounding walls, have a floor which suits its
purpose, and have a distinct purpose to serve.
If,
however, any one of these qualities is sufficiently strong, it alone may
establish the sense of urban space.
A
group of office buildings may contain a space around a poorly designed plaza or
a complex road intersection, the floor space being devoted entirely to traffic.
This is an urban space which has a sense of place in the city. It is both a
landmark and a traffic node, as well as an office node. An urban square may be
beautifully landscaped as a restful urban park, but it may lack entirely the
peripheral building facades which are needed for a sense of enclosure.
Here
we have a poorly enclosed space, but a space nevertheless. In another instance,
a particular place in the city may function as the locale of an important
activity while possessing neither physical enclosure nor appropriate floor.
Times Square in New York is such an example.
In
all these examples we have a sense of space. Such spaces are islands or oases
in the city. But urban spaces can also be linear corridors.
Avenues
and streets are linear urban spaces if they are enclosed on two sides or have
some element of unifying character—trees or uniform buildings. Corridor spaces
are spaces for linear movement. Island or oasis spaces are stopping places. Of
course the two can be interconnected. In fact, a spatial structure for an
entire city is exactly such an arrangement at the city’s total scale. Open
spaces, being nature brought into the city or open expanses allowed to remain
in their original state, cannot be described in quite the same manner used for
urban spaces. Their scale is given by the trees, shrubs, rocks, and ground
surface rather than their gross width and length. Their appearance is
characterized by the sight of natural verdure rather than surrounding
buildings. However, a vista of a distant building may accent a particular spot
and a bridge or pathway may complement nature’s forms. Open spaces in the city
have a wide variety of purposes. They are a complement and foil to urban form.
They are also reservoirs of land for future use. For an urban design survey, one
should study the spaces of the city as an overall structure. In doing this it
is helpful to classify spaces according to their actual use and to consider
formal urban spaces and the natural open spaces together.
For
example, one could start by mapping all the recreational parks in the city,
then the interconnected stream parks. The center city urban parks could be
mapped, and the main corridor spaces that lead to them or connect them. The
nodal spaces as well as the connector spaces all together would form the
spatial network. Such a survey would disclose a need for creating spaces in
certain areas, a need to improve existing spaces, and some possibilities for
connecting all of them. The survey of spaces should disclose a hierarchy of
spaces for rest and repose to spaces for meeting and bustling activity.
A
city’s entire system of public lands—roadways, schools, parks, civic buildings,
libraries, etc.—could be thought of as an open space network possibly
complemented here and there by public buildings. In an urban design survey we
look for the location, quality, and amount of open space in relation to the
city’s built-up areas.
Routes
Landscape,
architecture, and cities are seen as sequences as we travel along routes of
movement. Routes of movement affect considerably the appearance of the
landscape through which they pass and the architecture and cities which they
serve. Routes of movement are a principal determinant of urban form. In making
an urban design survey of the routes of a city, one should begin with the area
well beyond the city limits, far out in the country. The primary function of a
highway is to allow traffic to move, but a large part of that job depends on
how clear the route is in relation to the city. This aspect of highway
engineering—the “image-ability” of the highway—is a matter of revealing its
clarity of form and direction to the user. Too many highways have very poor
physical relationships to the areas they serve. Rather than helping to define
these areas, they often slash through them, actually acting as a blighting and
disintegrating force.
Routes
in the Countryside
In
the open landscape, existing and proposed routes should be examined and
assessed with a view to how well they relate to the natural terrain. How
artfully or awkwardly do routes traverse the landscape, revealing its prominent
features? Are vistas taken advantage of, or ignored? Some vistas might well be
presented with dramatic suddenness; others might be introduced gradually, or be
seen only in part.
Are
there dull areas which require embellishment? Perhaps the introduction of a
curve or rows of trees and shrubs could give more visual interest. Are there
obstructions to the enjoyment of the prominent natural features? Does the road
itself and its furniture mar the landscape or add beauty to it?
The
outlying routes of your city are the first introductions which approaching
visitors receive, giving them their major impressions. In making a visual
survey of routes, the routes should be charted, noting the character of the
terrain and the adaptation of the roads to it, the artful dramatization of
landscape features, the quality of added features, the accenting of the route,
its faults and possibilities for improvement or correction. Every new route
should be examined and
designed
on these bases as a matter of sound road engineering.
Approach
Routes and Surface Arteries
Approach
routes present cities to us. They must satisfy the visual requirement of
presenting architecture and cities in their best light, while enabling us to
find our destination readily. The two requirements go hand in hand. An approach
route must both inform us and conduct us.
The
major routes through the city are surface arteries—highvolume traffic streets
which carry buses and autos. They can be evaluated according to how they tie
into the expressway pattern, their clarity of form, their relation to the
cityscape, the shape of the building sites they pass by, and the way they pass
through existing districts.
Another
consideration is the street furnishings of the major surface streets. Can their
design be improved and a program for improving signs and traffic furniture be
started? How well do the through arteries tie into the pattern of slower-speed
local streets? How well do they tie into major garages and parking areas? How
easy is it to find a garage near your destination and to get into and out of
it? Most important of all, we must examine the relation between a street’s traffic
and buildings. A good index is the degree to which street traffic is actually
serving the buildings on the street, in contrast to traffic which is merely
passing through on the way to some other destination.
Local
Streets
The
through arteries serve an intricate network of small streets, along which cars,
buses, and delivery trucks stop and go. These streets carry a mixture of
vehicles and people. In surveying them, we examine whether vehicular and pedestrian
movement are in conflict with each other or aiding one another. Where do they belong
together and where not? Are pedestrians forced to wait for long periods of time
to cross streets, or are pedestrians free to cross streets anywhere? Is safety
achieved by the use of stoplights or by grade-separated pedestrian crossings? Is
the vehicular traffic strictly local, or is much of it through traffic? Can
this through traffic be relocated? How can existing small streets be protected
against the intrusions of through traffic? What is the dimensional scale of the
intimate local streets? How do they relate to the size of their districts? Can
these patterns be improved and strengthened?
These
comments illustrate that an inquiring survey raises many questions and
stimulates many ideas. As we elaborate on the pathdistrict-edge-landmark-node
framework, we find that some of them require more attention than others. Degree
of emphasis on one aspect or another will depend on the size of the city or the
urban sector being surveyed. On the large-scale survey of the whole city, its
paths, districts, and open spaces, for example, may be the predominant elements.
However, at all levels, the examination of the districts of the city
will probably require the greatest effort.
The Districts of a City
Every city consists of a series of parts which we refer to as
districts or enclaves or sectors—or perhaps as quarters, precincts, or areas.
They are distinguishable in that they have dominant and pervasive characteristic
features. Our mental images of cities consist, to a large extent, of the
arrangement of these parts. Some are distinct, some overlap others, some are
uniform, some are very complex. Almost all are in a process of change, which
further affects their appearance and their size. A very small town has at least
several distinguishable areas; a metropolis may have fifty or a hundred. The
pattern of districts is closely related to the pattern of routes. The size of a
district may be determined by the nature of the internal routes serving it. A
commercial center, for example, can usually be traversed on foot or by a short
cab ride. A residential section may often have local community facilities which
can be reached on foot, although its gross size may be far beyond the limits of
pedestrian traverse.
The districts of a city vary considerably in their strength of
character. Districts which do have very strong characters often develop identifying
names—Wall Street, Georgetown, Beacon Hill, Greenwich Village, the Loop. Other
districts with less assertive character often bear names related to their
historic origin—Market Street or Main Street, Foggy Bottom, Silver Spring,
Brookline. American cities, like most cities of the world, reflect their
characteristics of culture, growth, and development in an urban nomenclature.
In the United States this nomenclature includes: “downtown,” the
original center; “uptown,” the enlargement of the original center; “midtown,”
an offshoot of both; “Chinatown” and “Harlem,” ethnic areas; “the other side of
the tracks,” characterizing poor residential areas in the shadow of factories;
“the waterfront”; “the outskirts.”
Basically, there are two things to look for in discerning the
various districts of a city: physical form and visible activity. For example, in
a commercial center the types of buildings, the signs, the demolition and
construction activity, the crowds of rushing people, the cabs and buses, the
parking facilities—all these identify the place for us.
On the other hand, in a residential area we have the houses,
their spacing, the trees, the milk wagons, the parked cars, the children playing,
the occasional neighborhood stores and schools. The sum impression of the
individual parts and their relationships conveys to us the existence of a
particular district of a city—a part in relation to a whole.
Few, if any, cities can be neatly compartmentalized in this way.
The most prominent enclave may dissipate visually at its periphery. Most urban
enclaves lack outstandingly prominent characteristics. Further, complexity in
an urban enclave should not be mistaken for confusion. Urban complexity—the
intense intermixture of complementary
activities—is one of the major reasons for cities and the spice of
urban life. One must also distinguish between uniformity amounting to dullness,
and unifying architectural and landscape elements. constituting visual
cohesiveness, especially in the face of great variety. We should search for
answers to the following;
Components: What are the
principal component districts of the city? Where do they begin and end? What
are their characteristics, physically and as defined by activity? How apparent
are they?
Size: What is the size of a
district—its shape, density, texture, landmarks, space?
Appearance: Regarding their
physical appearance, what are the characteristics of building forms, building
density, signs, materials, greenery, topography, route-pattern landmarks? What
is the nature of the mixture of different building types?
Activity: Regarding visible
activity, what are the principal clues of the activity of an area—the kinds of
people, when and how they move about? What are the key visual elements—the things
principally seen—which establish the character of a district?
Threats: What are the
threats to a district? What external elements, such as a through road, threaten
the health and survival of district? How is the district changing? Is it
changing its position? Is an edge decaying? Is an edge advancing, perhaps into
a peripheral district?
Emergence: Are there latent
districts struggling to emerge, such as a new in-town residential section?
Relation: How do all these
parts relate to each other and especially to the route patterns of the entire
city? Finally, what are the areas in a city that cannot be classified easily,
that lack cohesion in form and character? Are some of these targets for urban
design work?
The Anatomy of a District
Having distinguished the separate parts of the city, it remains to
go one step further and survey the parts individually—to diagnose the
districts, the parts which constitute the whole. In surveying the visual
aspects of a district or enclave we should be asking:
Form: What is the physical form of
the place—form and structure in three dimensions and in broad outline? What is
the density and character of the buildings? What is the spacing of the
buildings? How does it vary? What is the greenery of the place? How would you
describe the paving, the signs, the night lighting? How uniform or how varied
is the whole, or sections of it? Can a district be further dissected into
meaningful places within it? What are these places like? What are the physical
patterns of the place? What are the patterns and the linear and focal points or
urban spaces within the district?
Activity: What do people do
there? How well does architecture and the district serve people? What are the
natural groupings of different activities within the district? How does the
activity pattern change according to the time of day, week, or season? How
lively are the central city areas? How does the local climate affect life in
the areas? What are the detrimental aspects of the place?
Features: What are the
features of the district—the major hubs or nodes, landmarks, and vistas? What
are the major magnets, generators, and feeders? In a busy center-city area,
what are the oases, the places of repose? In a quiet residential section, what
are the hubs, the places of community focus?
Paths: What are the principal paths
of movement in a district? How are they differentiated? How well do they serve
the people there? How well do they connect to the larger network of paths? Are
the actual physical dimensions of the paths adequate or excessive? How do they
determine the physical limits of the districts?
Centers: What are the
features of a district that serve a symbolic civic role? What are these places
like? Are they lively or lifeless? How can they be made lively? Are they integral
parts of the areas around them? Are they part of the life of the community, or
are they inanimate symbols?
Intrusions: What are the
intrusions and detrimental features of a district? What are the blighting
features? Here again one must be careful to distinguish between enlivening
intermixtures and truly harmful elements. How much traffic can be tolerated on
a street before it is impaired? How little before it is dead?
Change: How is the district changing,
both in internal character and the adjustment of its periphery to change? Is
there a direction of growth? In which direction is the center of gravity
moving? Is the edge decaying? How can a decaying edge be invigorated? How can a
district be stabilized?
Improvement: Finally, how can
the formation of a new district be aided? What are the new elements of the city
that are struggling to emerge? Which marginal districts can be protected and
improved as part of the complementary complexity of the whole city? How would
you analyze and depict the important districts in your city? What strengths do
you discern, what weaknesses? What differences do you find between districts? Is
there significance in their relative positions and character?
Activity Structure
An examination of districts and nodes reveals that there are
certain spots in the city that have characteristic functions. Generally speaking,
these districts fall into such categories as places of living, working,
shopping, traveling, leisure, recreation, and learning. There is a logic to the
location of these activities and there are definite visual results in their
deployment and interrelationships. Density, topography, and transportation
routes all affect an urban activity structure.
For example, a high-density residential area will have a central
shopping cluster which many of its clients can reach on foot. A low density residential
area will more likely be served by a shopping center reached by automobile, its
use shared with other lowdensity areas. Topography can dictate the location of
routes and therefore the location of centers and subcenters. Topography can
also dictate the location of hospitals and airports.
New transportation patterns can alter an existing urban
structure by causing the relocation of facilities which depend on a high degree
of public access. Shopping centers on a city’s periphery are in large measure a
consequence of circumferential expressways. Small neighborhood shopping centers
on radial routes are approximate indicators of the centers of residential
districts.
A large-scale study of activity structure will reveal the
general centers of work and residence and a physical correspondence between activity
and district. When tied into an examination of major routes of movement, the
relation between activity and circulation access becomes clear. So do points of
conflict and areas in transition.
Orientation
If there is logic in the arrangement of a city’s anatomy and if
that arrangement is visibly evident—articulated—the sense of orientation will
be strong. If there is logic but little or no visible articulation, a city can
be confusing even to the point where it arouses a high degree of frustration
and anxiety, and the feeling of being lost. Landmarks are a prime aid to
orientation, On the overall scale of the city, prominent landmarks are tall
verticals like central skyscraper groups, natural features such as rivers or
shores, district edges, unique vistas, clear routes which lead to and from a
known place, and districts with strong visual characteristics.
Orientation studies should be made on the scale of the whole metropolis
as well as small enclaves such as shopping areas, commercial areas, or
institutional groupings. Design programs to improve the sense of orientation
are particularly important where there are many visitors, as at an airport, or
downtown, or at a shopping center. The logic of arrangement and its visible
evidence, achieved through design, is the prime device for improving
orientation. Signs are a secondary device. Where signs are relied on too
heavily, they may add to the confusion or go unheeded.
Orientation studies can be made by the urban design surveyor himself
if he is unfamiliar with the area, but they are best made by an interview-map
technique.
Details
A visual survey of urban details should, therefore, include sign
studies.
More broadly, it includes the quality and conditions of park
benches, wastebaskets, streetlamps, pavements, curbs, trees, fences, doorways, shopwindows,
etc.—the street furniture and hardware of the city.
Pedestrian Areas
A large part of the difficulty in our cities arises because we
have neglected the pedestrian. Walking will always remain a prime mode of
transportation. Some areas of the city depend on it almost entirely as a means
of communication and intermovement. Many new shopping centers and college
campuses are models of design for pedestrian circulation. Older areas in the
city need similar treatment. We must be careful, however, in concluding that
all the trouble comes from the mixture of pedestrians and cars. Many city
streets would be lifeless without cars. The problem comes when cars prevent the free flow of
pedestrians. It is possible to have both—cars and pedestrians—in busy urban
centers if the cars operate at very low speeds and if through traffic is
reduced to the utmost.
A good way to check the quality of pedestrian movement in a busy
area is first of all to examine the sidewalks for their adequacy— width,
paving, condition, protection from rain and hot sun, and sidewalk outfittings
such as benches. Second, one should walk through a pedestrian area taking
several different paths to locate the main points of interrupted movement,
generally speaking the intersections and crossovers. Too many intersections in
city centers are designed to allow a maximum flow of traffic and to subjugate the
pedestrian to long and annoying waiting periods. An answer to this problem is
pedestrian safety islands and reduced-speed traffic, Pedestrian crossings
should be frequent and convenient. A shopping street which is difficult to
cross cuts the pedestrian-shop contact in half. The ideal answer to this
problem is the separation of cars and people onto different levels, the cars
below and the people above. But this is impossible in most cities. In smaller
towns it is possible to make the downtown area a pedestrian-oriented zone by
providing a convenient bypass road for through traffic and by providing
adequate parking garages around the downtown area itself. The essential
approach to this problem lies in regarding a downtown area, or any center for
that matter, as a stopping place and not a place for through traffic. In
outlying areas the same principles of pedestrian flow can be studied, to
examine the pedestrian linkages between neighborhoods and their centers.
Children should not have to cross busy streets, and the centers themselves
should be at the center of a convenient walking as well as auto-shopping
radius.
Vista
and Skyline
Every city has a few
striking vistas—of it and from it. Approaching Dallas, Texas, from the west,
one sees a towering cluster of skyscrapers rising from the plains. The approach
to Chicago along Lake Shore Drive is a dramatic urban entrance, as is the
approach to New York City from the West Side Highway, and Salt Lake City
through a pass in the Rockies. These are the major vistas of the city, and they
must be protected from intrusion. From the city, too, there are always a few
dramatic outlooking vistas. Sometimes these vistas are modest, but still of
great importance in characterizing the city. The slot views down the sloping streets
of San Francisco afford fine vistas of the bay. Similar slot views down the
side streets of Richmond, Virginia, afford glimpses of the surrounding
countryside across the river. The views into and out of a city are precious
assets. They are an important part of an urban design plan. Some views of the
city are in need of legal protection, like the shores of the Potomac across
from Mount Vernon. Other views can be complemented by well-poised pieces of
architecture, like the buildings of West Point on the palisades of the Hudson
River. An urban design survey should note the major views of the city and
different points around the city, particularly points of approach. It should
also note the major aspects of vista out of the city from points within.
Evaluations should be made of improvements needed in both types of vista.
A further study
can be made of a city’s skyline. The city’s skyline is a physical representation of its facts of life. But a skyline
is also a potential work of art. An urban skyline is its collective vista. It
is often the single visual phenomenon which embraces the maximum amount of
urban form. Every building that alters the urban skyline should be studied for
its effects on the overall view. Many skylines can be improved, particularly by
adding a small counterpoint tower at an outlying location. It is interesting to
compare the visual effect of a cluster of towers with a single tower. A
prominent single tower must be designed as a chef
d’oeuvre if it is to be admired. It is
too much on display to be mediocre. However, a cluster of towers, like a group
of statues, can tolerate less distinguished design, If a tower is to be built
at a prominent outlying location, it may be helpful to consider double or
triple towers rather than a single shaft. Twins or triplets can be more
modestly designed, and their profile as an ensemble can then be more assertive
than the single shaft. On the other hand, an elegant profile may be easier to
achieve with the single shaft.
Manhattan can be seen on its two long sides and from the south across
large expanses of water. It can be seen as a whole composition of masses and
lights. At night the highways that ring the city are marked out by their evenly
spaced and specially hued dots of highway lighting—ribbons of dotlike lights
against a splash of electric stars. Further, Manhattan’s several suspension
bridges now have their catenary cables strung with lights. On a clear night
several bridges can be seen simultaneously. The random lights, the even
ribbons, and the gracefully curved bridge lights are one of the wondrous urban sights
of the world. This illumination theme could well be used as a model in
principle for every city. A visual survey of a city at night could suggest just
when and how new lights could be added to achieve a similar composition,
Nonphysical Aspects
There
are many nonarchitectural aspects of urban character: the New Year’s Day parade
in Philadelphia, the Rose Bowl parade in Los Angeles, Mardi Gras in New
Orleans. These are a very large part of the image of a city and a large part of
its personality. Architects can do much to improve the appearance and urban
quality of cities by recognizing them and making better provision for them. Every
city has a history, linking it to its origin, and present in the minds of its
population. Visible signs of that history can constitute a major aspect of its
appearance. Architectural provision can be made for public ceremonies and
events, In new areas the inclusion of some visible symbols of the old city’s
personality give continuity and character to the new. Every city has a
particular purpose which should be expressed architecturally. Boston is a
center of learning as well as commerce. New York is a center of culture as well
as finance. Miami is a center of leisure. Pittsburgh is a center of steel
production. Detroit is our automobile manufacturing center.
Problem Areas
As a
result of the visual survey, it is helpful to map the problem areas of a city
alone. This map would stand as the urban design diagnosis of ills. It would
show points of conflict between pedestrians and autotmobiles, areas with little
or no sense of orientation, nondescript or gray areas, ugliness, communities
lacking form and definition, areas with confusing signs, confusing circulation
elements, incomplete routes, marred vistas, etc. As a diagnosis of ills, such a
map would be a direct source of ideas for action programs.
Some
Personal Techniques for Surveying
Anyone who attempts a
visual survey of his city will undoubtedly develop his own technique and, very
likely, a personal vocabulary, In our discussion of this subject we mean
primarily to suggest the many different aspects of form that can be examined.
But it is also important to be able to link all of the separate aspects of form
into a chain of related aspects. One observer, therefore, might want to
assemble his vocabulary of form elements into a coherent whole, such as the following:
Paths, landmarks, nodes, districts, and edges are the skeletal elements of a
city form. On that basic framework stand embellishing characteristics which all
together constitute the personality of a city.
Suppose that we think
of urban form in the following way: A city or town is generally thought of in terms
of size—its population and physical extent. Size is closely linked to shape—the
physical outline in horizontal plan form and vertical profile or contour. Size
and shape are qualified by pattern—the underlying geometry of city form. Size, shape,
and pattern are further modified by density—the intensity of use of land by
people and buildings. Density is determined by urban texture and grain—the
degree of homogeneity or heterogeneity of use by people or buildings.
We can usually identify
the parts of a city by their dominant visible activities. Often these activities
are complementary, yet sometimes they are conflicting. It is important not to
mistake complexity for conflict; complexity is the spice of urban life. The
bustling urban centers are magnets of the city. People are the generators which
require magnets around which to rally. Feeders are the links and paths which
connect the two.
These areas of dominant
visible activity exist in sequence as linked accents. The periodic occurrence
of accents in sequence is rhythm. The disposition in a sequence has, of course,
visible manifestations. Thus, accents in a sequence produce a modulation of
visual intensity—varying degrees of richness of visual experience. Our use of
the various parts of a city depends upon their degree of accessibility. Demands
for accessibility produce channels of flow. Channels of flow vary in intensity,
according to the time of day, week, or season, and thereby establish patterns
of movement. Patterns of movement help define districts and act as links.
Visible
activity, road signs, store signs, building signs, and symbolic objects are messages to us which convey purpose.
They are clues to the organization of urban form.
The
visual experience of a city is enriched by major vistas—views of large
portions and major elements of the city, and of contrasting natural scenery. We
are highly conscious of the nature of land surface (generally thought of
as topography). We are aware of going up, going down, and the quality of the
surface upon which we move. Natural landscape features form important borders
or edges in cities.
Buildings
are the immobile masses of a city. Arrangements of buildings form patterns
of mass. Arrangements of buildings also form urban spaces which
exist as patterns of channels and reservoirs.
Entrances
to a city can be accented by portals, the doorways to a city or a
district in it. Pauses or relaxations in an intense area are oases—places
inducing repose. They are passive accents which complement intense activity.
Districts in a city are characterized by a pervading continuity of use,
purpose, and appearance, Some districts are oriented to particular types of
people or particular age groups. A fine distinction can even be made between
masculine and feminine districts.
Our
knowledge of these visible phenomena, the presence of visible landmarks,
pattern, shape, etc., imparts a sense of orientation— a sense of where
we are and where things are in relation to us. A sense of orientation is basic
to our understanding, familiarity, and well-being in a city. We are conscious
of the age of a city and its parts, the newness and oldness in buildings
and places. We must avoid the danger of equating oldness with decay, or newness
with amenity. In his work, the urban designer must transcend time and relate
all parts of the city to each other. A major objective of urban design is to relate
different kinds of buildings, regardless of differences in architectural style,
age, or use.
Recording
the Results
Visual
surveys are most readily recorded as simple maps accompanied by sketches,
photographs, and brief notes. The maps can be base maps of the city, at the
scale or scales of the survey. The sketches, photographs, and notes can be
attached to the maps and the whole study put on display or published as a
report, The maps and their notations are best done in a cartoon style and
notations of certain features best indicated as a graphic symbol.
Routes
of movement can be indicated by arrows, parking garages as a spiral, landmarks
as large X’s, vistas as sector lines, points of conflict in red, “gray areas” in
gray, etc. One map should show the sum total of the general form of the city
and its features. The remaining maps should complement this as a series of
detailed aspects of the city’s form.
1.
Topography
2.
Microclimate—sun, wind, and storm directions
3.
Shape
4.
Patterns, textures, and grains
5.
Routes
6.
Districts
7.
Landmarks and nodes
8.
Open spaces
9.
Vistas
10.
Magnets, generators, and linkages
11.
Special activity centers and overall activity structure
12.
Hubs of intense visual experience
13.
Strong and weak areas of orientation
14.
Sign areas
15.
Points of conflict
16.
Historic or special districts
17.
Community structure
18.
Areas for preservation, moderate remodeling, and complete overhaul
19.
Places needing clarifying design elements
20.
Sketch maps produced by the “man on the street” to discern the urban features
and forms prominent in the public’s eye.
Each
of these maps should be illustrated by a few salient sketches or photos that
show exactly what a map symbol represents and also a series of pictures which
characterize the area.
Conclusion
Music
can be described and discussed with considerable precision and insight because
it has a vocabulary and a body of literature. At present painting also enjoys
this advantage. So does architecture, to an extent. Up to now the complex
modern city has lacked a precise vocabulary for discussing its form and
appearance. If we formulate such a vocabulary we will be able to discuss urban
form with clarity,
We
will also be able to discuss the effects of various actions and policies that
affect the city in terms of its buildings, parks, streets, and places.
Therefore we will be better able to discuss its design. While developing this
language and engaging in conversations on urban form, we must avoid overly
abstract terms. Unlike the complexities of modern music or painting, the city
is familiar to everyone and can always be described in simple terms. That may
be the best test of any vocabulary.
Robert
Regis
Summary
The
Piazza di Spagna and the Scala di Spagna (Spanish Steps) are
among the few and truly unique examples in urban design where stairs, by
themselves, serve as a visual and spatial focal center. The sequence of space
one experiences in this Late Baroque piazza and stairway (1721–25) by
Alessandro Specchi and Francesco dé Santis,
with
its 137 steps, is a significant city space in central Rome. The
sketchbook—using visual notation and drawing to explore formal, spatial
relationships, details and activity of urban places—provides the urban designer
a method of observation, documentation and understanding.
Key
words
Rome,
sketchbook, Spanish Steps, visual analysis
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