1

The activity called city planning, or urban design, orjust planning, is being sharply questioned. It is notsimply that these questions come from those whoare opposed to any kind of planning. Nor is it becauseso many of the physical effects of planning seem tobe piecemeal. For example roads can be proposedwithout any real consideration of their effect onenvironment; the answer to such proposals couldbe that they are just not planning at all. But it is notjust this type of criticism that is raised. The attack ismore fundamental: what is being questioned is theadequacy of the assumptions on which planningdoctrine is based.

What are those assumptions? To put this in themost general terms, they resolve themselves into twopowerful lines of thought. The first, which stems fromthe work of the Viennese writer Camillo Sitte, whosebook City Planning according to Artistic Principles waspublished in 1889, can be called the doctrine of thevisually ordered city. To Sitte the total city plan is theinspired and the all encompassing work of art. ButSitte went further: civic art must be an expression ofthe life of the community, and finally ‘works of artcannot be created by committee but only by a singleindividual’ (Collins 1965).‡ The planner then is theinspired artist expressing in the total city plan theambitions of a society. There are indeed many who,though not prepared to accept this total – it wouldnot be inaccurate to say this totalitarian – role of the

planner, have nevertheless been profoundly influ-enced by Sitte’s doctrine of the visually ordered city.The doctrine has left its mark on the images that areused to illustrate high density development of cities. Itis to be seen equally in the layout and arrangement ofGarden City development. The predominance of thevisual image is evident in some proposals that workfor the preservation of the past: it is again evident inthe work of those that would carry us on, by animagery of mechanisms, into the future. It remainscentral in the proposals of others who feel that,although the city as a total work of art is unlikely to beachieved, the changing aspect of its streets andsquares may be ordered visually into a succession ofpictures. The second line of doctrine is severely practi-cal. It can be called the doctrine of the statisticallyordered city. We know it well. It is the basis of thoseplanning surveys in which uses are quantified, sortedout and zoned into particular areas; population densi-ties are assessed and growth and change predicted. Itis the raw material of the outline analyses and thetown maps of the 1947 Act.

Now it is precisely these two aspects of planning(the first concerned with visual images and the sec-ond with procedure, and sometimes of course usedin combination by planners), that were so sharplyattacked by Mrs Jane Jacobs in her book The Deathand Life of Great American Cities (1961). For MrsJacobs, both ‘the art of city planning and its compan-ion, the pseudo-science of city planning, have not yetembarked on the effort to probe the real world of

8The grid as generator†

Leslie Martin[1972]

†Some parts of ‘The grid as generator’ were used in the Gropius Lecture at Harvard University in June 1966. The argu-ment was developed later into the theme delivered at the University of Hull under the title, ‘The Framework of Planning’,as the inaugural lecture by Leslie Martin as Visiting Ferens Professor of Fine Art. It is presented here in essentially that form.‡See also a review of both Sitte 1889 and Collins 1965 in L. March (1966).

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living’. For her a city can never be the total work of art,nor can there ever be the statistically organised city.Indeed, to Mrs Jacobs, the planning of any kind oforder seems to be inconsistent with the organicdevelopment of cities which she sees as a direct out-come of the activities of living. Planning is a restrictiveimposition: the areas of cities ‘in which people havelived are a natural growth … as natural as the beds ofoysters’. Planning, she says, is essentially artificial.

It is of course just this opposition between‘organic’ growth and the artificial nature of plans,between living and the preconceived system withinwhich it might operate, that has been stressed somuch in recent criticism. Christopher Alexander in adistinguished essay ‘A city is not a tree’ puts thepoint directly when he says:

I want to call those cities that have arisen spon-taneously over many many years ‘natural cities’.And I shall call those cities or parts of cities thathave been deliberately created by planners ‘arti-ficial cities’. Siena, Liverpool, Kyoto, Manhattan,are examples of natural cities. Levittown,Chandigarh and the British New Towns areexamples of artificial cities. It is more and morewidely recognised today that there is someessential ingredient missing in the artificial cities(Alexander 1966).

Let us consider this. First of all would it be true tosay that all old towns are a kind of spontaneousgrowth and that there have never been ‘artificial’ orconsciously planned towns in history? Leaving onone side ancient history, what about the four hun-dred extremely well documented cases of new towns(deliberately planted towns) that Professor Beresfordhas collected for the Middle Ages in England, Walesand Gascony alone (Beresford 1967)? What aboutthe mediaeval towns such as those built in Gasconybetween 1250 and 1318 on a systematic gridironplan? All these towns were highly artificial inAlexander’s sense. The planted town, as ProfessorBeresford observes, ‘is not a prisoner of an architec-tural past: it has no past’. In it the best use of landmeant an orderly use, hence the grid plan. In sitingit and building it estimates had to be made about itsfuture, about its trade, its population, and the sizeand number of its building plots. This contributes ahighly artificial procedure.

But it is of course by no means uncommon. Indeedit is the method by which towns have been createdin any rapidly developing or colonial situation. A recent book by John Reps, The Making of UrbanAmerica (1965) is a massive compendium of the

planting of new towns throughout America, practi-cally all of them based on highly artificial gridironplans. He points out that there is a sense in whichnot merely cities but the whole of Western Americais developed within an artificial frame: ‘the giant grid-iron imposed upon the natural landscape by … theland ordinance of 1785’.

The coloniser knows that the natural wildernesshas to be transformed: areas must be reserved foragriculture as well as plots for building. The man-made landscape is a single entity: cities and theirdependant agricultural areas are not separate ele-ments. All these things are matters of measure andquantity. They are interrelated between themselvesand numbers of people. The process demands a qual-ity of abstract thought: a geometry and a relationshipof numbers worked out in advance and irrespective ofsite. The 20-mile square plan for the proposed colonyof Azilia, the plans of Savannah and Georgetown, aretypical examples of this kind of thought. WilliamPenn’s plan for Philadelphia, the plans of such townsas Louisville, Cincinnati, Cleveland, New York Cityitself, Chicago and San Francisco, are all built on thebasis of a preconceived frame.

In the case of the mediaeval towns described byBeresford, whilst some failed, a high proportion suc-ceeded in their time. In a large number of Americancities, the artificial grid originally laid down remainsthe working frame within which vigorous moderncities have developed. It is quite clear then that anartificial frame of some kind does not exclude thepossibility of an organic development. The artificialgrid of streets that was laid down throughoutManhattan in 1811 has not prevented the growthof those overlapping patterns of human activitywhich caused Alexander to describe New York as anorganic city. Life and living have filled it out but thegrid is there.

And this brings us closer to the centre ofAlexander’s main argument What he is criticising inthe extended content of his essay, is the notion thatthe activities of living can be parcelled out into sep-arate entities and can be fixed for ever by a plan.The assumption is common in much post-war plan-ning. Consider an example. Housing is thought ofin terms of density: 75, 100, 150 people per acre.That will occupy an area of land. Housing requiresschools and they need open space: that will occupyanother specific area. These areas in turn may bethought to justify another need: an area for recre-ation. That is one kind of thought about planning. Butalternatively an effort may be made to see the needsof a community as a whole. It may be discovered

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that the way housing is arranged on the ground mayprovide so much free space that the needs of schoolsor recreation will overlap and may even be containedwithin it (Martin 1968).

In the first instance the uses are regarded as self-contained entities: Alexander equates this kind ofthinking with an organisation like that demonstratedby a mathematical tree. In the second instance thepatterns of use overlap: the organisation in this caseis much closer to a far more complex mathematicalstructure: the semi-lattice. The illustration of the sep-arate consideration of housing, schools and openspace is elementary. But it is Alexander’s argumentthat whole towns may be planned on this basis.And it is this attempt to deal with highly complexand overlapping patterns of use, of contacts and ofcommunications in a way which prevents this over-lap from happening that Alexander deplores. Hencethe title of his paper: ‘A city is not a tree’. In thissense of course he is correct. But the argument canbe put in a different way. It can be argued that thenotion (implied by Mrs Jacobs) that elaborate pat-terns of living can never develop within a precon-ceived and artificial framework is entirely false. Thiscan be developed by saying that an ‘organic’ growth,without the structuring element of some kind offramework, is chaos. And finally that it is only throughthe understanding of that structuring frameworkthat we can open up the range of choices andopportunities for future development.

The argument is this. Many towns of course grewup organically by accretion. Others, and they arenumerous and just as flourishing, were establishedwith a preconceived framework as a basis. Both arebuilt up ultimately from a range of fairly simple for-mal situations: the grid of streets, the plots whichthis pattern creates and the building arrangementsthat are placed on these. The whole pattern ofsocial behaviour has been elaborated within a lim-ited number of arrangements of this kind and this istrue of the organic as well as the constructed town.Willmott and Young, studying kinship in the EastEnd of London (1957), were able to show thateverywhere elaborate patterns of living had beenbuilt up. All these elaborations, and a great varietyof needs, were met within a general building pat-tern of terraces and streets. Change that pattern andyou may prevent these relationships from develop-ing or you may open up new choices that were notavailable in the original building form.

The grid of streets and plots from which a city iscomposed, is like a net placed or thrown upon theground. This might be called the framework of

urbanisation. That framework remains the control-ling factor of the way we build whether it is artificial,regular and preconceived, or organic and distortedby historical accident or accretion. And the way webuild may either limit or open up new possibilitiesin the way in which we choose to live.

The understanding of the way the scale and pat-tern of this framework, net or grid affects the pos-sible building arrangements on the land within it, isfundamental to any reconsideration of the structureof existing towns. It is equally important in relationto any consideration of the developing metropoli-tan regions outside existing towns. The pattern ofthe grid of roads in a town or region is a kind ofplayboard that sets out the rules of the game. Therules outline the kind of game; but the playersshould have the opportunity to use to the full theirindividual skills whilst playing it.

2

How does the framework of a city work? In whatway does the grid act as a generator and controllinginfluence on city form? How can it tolerate growthand change?

The answer to these questions is best given byhistorical examples, and in order to give the argu-ment some point we can deliberately choose themost artificial framework for a city that exists: thegrid as it has been used in the United States, and sowell illustrated by Reps (1965).

We can start with the notion that to the coloniserthe uncultivated wilderness must be tamed into asingle urban–rural relationship. In the plan for theproposed Margravate of Azilia (the forerunner ofthe colony of Georgia) the ground to be controlledis 20 miles square, or 256,000 acres. Implicit in thesubdivisions of this general square is a mile squaregrid; and out of the basic grid the areas for farmland,the great parks for the propagation of cattle and theindividual estates are built up. At the centre is thecity proper.

The Margravate was never built, but the conceptof the single urban–rural unit and the principle of agrid controlled land subdivision within this remains.In the County map of Savannah, Georgia, made in1735, a grid of (slightly less than) one mile squaresub-divides a rectangle nearly 10 miles long and 6miles deep. Thirty-nine of these squares remainwooded areas: within this primary subdivision, fur-ther subdivisions create farms of 44 acres and 5-acregarden plots. These are the related grid systems of

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the city region. On the river front within this mainsystem is the city itself.

Now it is this city grid of Savannah that can beused as a first example of a city grid. A view ofSavannah in 1734 illustrated in John Reps’ bookdescribes the principle: the plots and streets of theembryo city are being laid out: some buildings arecomplete. The unit of the Savannah grid is square:it is called a ward and is separated from its neigh-bours by wide streets. Within each square (or ward)building plots for houses are arranged along twosides, the centre itself is open, and on each side ofthis open square are sites for shops and publicbuildings. Savannah grew by the addition of theseward units. In 1733 there were four units: in 1856no less than twenty-four. The city became a che-quer board of square ward units, marked out by thestreet pattern. But within this again, the plaid is fur-ther elaborated. The central open spaces of eachward are connected in one direction by intermedi-ate roads, in the other direction the central areasbecome a continuous band of open spaces andpublic buildings. Here is a unit grid with directionand orientation.

The second example of a grid is absolutely neu-tral. It lays down an extensive and uniform patternof streets and plots. The whole process can be illus-trated in one single large scale example. In 1811 thelargest city grid ever to be created was imposedupon a landscape. The unlikely site for this enter-prise was an area of land between two geophysicalprovinces in which a succession of tilts, uplifts anderosions had brought through the younger stratatwo layers of crystalline rock. These appeared asrocky outcrops under a thin layer of soil and vege-tation. Into their depressions sands and gravels hadbeen deposited by glacial action to create swampyareas through which wandered brooks and creeks.Some of these still wander into the basements ofthe older areas of what is now Manhattan.

In 1613 the original Dutch settlement was lim-ited to the tip of the island. In 1760 there was littleexpansion beyond this and contemporary illustra-tions depict to the north a rolling landscape. Taylor’splan of 1796 shows the first modest growth of a citylaid out on a gridiron pattern. Surveys in 1785 and1796 extending up the centre of Manhattan set outthe basis for a grid, and in 1811 the special StateCommissioners confirmed this in an 8 ft long planwhich plotted the numbered street system ofManhattan as far north as 155th Street. The planshowed 12 north–south avenues each 100 ft wideand 155 cross streets each 66 ft wide. The size of

the rectangular building plots set out by this gridare generally 600 ft by 200 ft. There were some publicopen spaces. (Central Park was of course carved outlater.) And it is this framework that has served thesuccessive developments of the built form from 1811to the present day.

The third example of a city grid is of interestbecause of its dimensional links with the land ordi-nance, suggested by Thomas Jefferson and passedby Congress in 1785. Under that ordinance a hugenetwork of survey lines was thrown across all theland north and west of the Ohio river (Robinson1916). The base lines and principal meridians of thesurvey divided the landscape into squares 36 mileseach side. These in turn were subdivided into 6-milesquares or townships and further divided into 36sections each one mile square. The mile squares arethen subdivided by acreage: the quarter section160 acres with further possible subdivisions of 80,40, 20, 10 or 5 acres. The 5-acre sites lend them-selves to further division into rectangular city blocks(not unlike those of Manhattan) and subdivisionagain into lots or building plots.

In 1832, according to Reps (1965), Chicago wasnot much more than a few log cabins on a swamp.The railway came in the mid-century and by theseventies and eighties a mile square grid had beenextended over a considerable area of the prairie andthe city framework had developed within thisthrough a plaiting and weaving of the subdivisionsthat have been described.

Here then are three types of grid, that of Savannah,the gridiron of Manhattan and that of Chicago.Each one is rectangular. Each one has admittedchange in the form and style of its building. Eachone has admitted growth, by intensification of landuse or by extension. Savannah, as it grew, tended toproduce a green and dispersed city of open squares(Fig. 8.1). In Manhattan, the small scale subdivisionof the grid and the exceptional pressure to increasefloor space within this, forced buildings upwards.Chicago spread, continually opening out the pat-tern of its grid. In each case the influence of theoriginal grid remains: each one offers different pos-sibilities and choices of building and of living.

In order to trace the influence of the grid, we canexamine the building arrangement that developedwithin it in New York. We can identify at once whatmight be called the streets and the system that isestablished by the grid. If we now use the languageof the urban geographers, we know that this definesthe general plot pattern. The building arrangementdevelops within this (Conzen 1962).

The grid as generator 73

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The stages of this latter process can be traced inthe early plans of Manhattan produced in 1850. Thegrid of roads is already built. Within this general plotpattern the separate building plots are being estab-lished. To the north, on the building frontier, there isa line of huts and shacks. Further south more perma-nent but separate buildings are being built. And inthe most developed area further towards the tip ofManhattan the full building arrangement has solidi-fied into connected terraces of four to six-storeyhouses arranged around the perimeter of the site andenclosing private gardens. Views of Manhattan in the1850s show a city developed in this way: and thispattern of building arrangement can still be seen inmany areas. At this point the building land is replete.A balance is maintained between the plot, theamount of building that it can reasonably supportand the street system that serves this.

But as the pressure for floor space increases, thebuilding form changes intensively at certain nodalpoints (Fig. 8.2). Deeper and higher perimeter build-ings first of all submerge the internal garden space.A process of colonisation of the individual buildingplots begins, so that larger areas of the general plotare covered by higher buildings. In 1916 the firstsingle building to occupy an entire city block rose a

sheer 600 ft; its roof space almost exactly equalledthe area of its ground plan. It was this building thatmost clearly illustrated the need for the compre-hensive zoning ordinances adopted that year, afterarduous study and political compromise, to safe-guard daylight in streets and adjoining buildings.But the grid now exerts a powerful influence: thelimited size of the grid suggests the notion thatincreased floor space in an area can only be gainedby tall buildings on each separate plot. The notionsuggests the form; the regulations shape it into zig-gurats and towers. Under the regulations that pre-vailed until recent years, if all the general buildingplots in central Manhattan had been fully devel-oped, there would have been one single and univer-sal tall building shape. And, to use an old argumentby Raymond Unwin (1912), if the population ofthose buildings had been let out at a given moment,there would have been no room for them in thestreets. The balance between area of plot, area of floorspace and area of street has disappeared.

Now these descriptions of the grid, which havebeen used as a basis for the argument, have exposedthe points at which it can be, and has been, extensively attacked for more than a century. A grid

74 Urban Design Reader

FIGURE 8.1The basic plot layout of Manhattan is shown in thedotted lines. On this, four wards of the Savannah typeof development have been superimposed. Theexample shows the effective way in which this layoutopens up broad bands of green space and publicbuildings running across the developed areas.

FIGURE 8.2The basic plot layout of Manhattan is shown again inthe dotted lines. The building forms show threestages of development including the original 4–6-storey perimeter form with a garden at the centrewhich was characteristic of the city in the 1850s, andtwo examples of the more intensive developmentduring the present century.

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of any kind appears to be a rigid imposition on thenatural landscape. It is this reaction against the gridthat is voiced by Olmstead and Vaux writing in sup-port of their design for Central Park in 1863: ‘Thetime will come when New York will be built up, whenall the grading and the filling will be done and thepicturesquely varied rocky formation of the islandwill have been converted into formations for rowsof monotonous straight streets and piles of erectbuildings’ (Reps 1965).

In their opposition to the grid, the relief from itsmonotony became a specific aim. Central Park itselfis an attempt to imitate nature and to recreate wildscenery within the grid.† The garden suburb with itscurving streets is one form of attack on the grid sys-tem, and an attempt to replace it. And at the end ofthe century, the Chicago Fair (1893), Cass Gilbert’sschemes in Washington (1900), and the plans forSan Francisco (1905) and Chicago (1909) byBurnham are another attempt to transform theurban desert by means of vistas and focal points,into the ‘city beautiful’. However, we recognise atonce a contrast. The various types of grid that havebeen described opened up some possible patternsfor the structure of a city but left the building formfree to develop and change within this. The plans ofthe garden city designers or those concerned withmaking the ‘city beautiful’ are an attempt to imposea form: and that form cannot change.

It is not possible to deny the force behind thecriticisms of the grid. It can result in monotony: socan a curvilinear suburbia. It can fail to work: so canthe organic city. What has been described is a process.It is now possible to extract some principles. Artificialgrids of various kinds have been laid down. Thechoice of the grid allows different patterns of livingto develop and different choices to be elaborated.The grid, unlike the fixed visual image, can acceptand respond to growth and change. It can be devel-oped unimaginatively and monotonously or withgreat freedom. There can be a point at which the original grid fails to respond to new demands(Fig. 8.3). As in Manhattan, it congeals. And it is atthis point that we must try to discover from the oldframework a new ordering principle that will openup new opportunities for elaboration by use.

It is precisely this that Le Corbusier underlinedwhen he paid his first visit to New York in 1935 andmade the comment: ‘What about the road?’ (LeCorbusier 1939, 1947.) The diagrams by which heillustrates this remark show the regenerative processthat is necessary (Fig. 8.4). By increasing the size ofthe street net in Manhattan, Le Corbusier shows thatthe grid ceases to restrict. New building arrange-ments become possible and the balance betweenplot, building and street can be restored.

3

In the case of these American cities the grid or frame-work can be regarded as an ordering principle. Itsets out the rules of the environmental game. Itallows the player the freedom to play with individualskill. The argument can now be extended by sayingthat the grid, which is so apparent in the Americanexamples, is no less controlling and no less impor-tant in cities nearer home that would normally be

†This movement which began with gardens, was less appropriately applied to city layout. In Olmstead’s words, ‘lines ofroads were not to press forwards’. Their curving forms suggest leisure and tranquility. Compare this with the almost con-temporary (1859) statements by Cerda in his plan for Barcelona in which there is ‘a reciprocal arrangement between thatwhich is contained’ (building plot and arrangement) and ‘that which contains’ (grid and street system). ‘Urbanisation isan appendix to universal movement: streets are for movement but they serve areas permanently reserved and isolatedfrom that movement which agitates life’ (the environmental area).

FIGURE 8.3The illustration shows building plot development inits most intensive form.

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called organic: London, Liverpool or Manchester.They too have a network of streets and howevermuch the grid is distorted, it is there. At a certain scaleand under certain pressures the grid combined withfloor space limits and daylight controls is just aslikely to force tall building solutions. And it is just aslikely to congeal. It lends itself just as readily toregenerative action. The theoretical understandingof the interaction between the grid and the built formis therefore fundamental in considering either exist-ing towns or the developing metropolitan regions.

The process of understanding this theoreticalbasis rests in measurement and relationships and itgoes back certainly to Ebenezer Howard. LionelMarch has recently pointed out a number of inter-esting things about Howard’s book Tomorrow: apeaceful path to real reform first published in 1898. Itis a book about how people might live in towns andhow these might be distributed. But the importantthing is that there is no image of what a town mightlook like. We know the type of housing, the size ofplot, the sizes of avenues. We know that shopping,schools and places of work are all within walkingdistance of the residential areas. On the basis of thesemeasurements we know the size of a town and thesize of Howard’s cluster of towns which he calls acity Federation. We know the choice that is offered

and we know the measurements that relate to these.If we disagree with the choice we can change themeasurements. Lionel March (1967) took Howard’sopen centred city pattern linked by railways andshowed that it could be reversed into a linear pattern linked by roads and that such patternscould be tested against the land occupied by ourpresent stock of building and our future needs.

Now that is theory. It contains a body of ideaswhich are set down in measurable terms. It is opento rational argument. And as we challenge it success-fully we develop its power. The results are frequentlysurprising and sometimes astonishingly simple.Ebenezer Howard’s direct successor in this field wasRaymond Unwin. The strength of his argumentalways rests in a simple demonstration of a mathe-matical fact. In an essay ‘Nothing gained by over-crowding’ (Unwin 1912), he presents two diagramsof development on ten acres of land. One is typicaldevelopment of parallel rows of dwellings: the otherplaces dwellings round the perimeter. The secondplaces fewer houses on the land but when all thevariables are taken into account (including the sav-ings on road costs) total development costs can becut. From the point of view of theory, the importantaspect of this study is the recognition of related fac-tors: the land available, the built form placed on this,and the roads necessary to serve these. He demon-strated this in a simple diagram.

Unwin began a lecture on tall building by a refer-ence to a controversy that had profoundly movedthe theological world of its day, namely, how manyangels could stand on a needle point. His method ofconfounding the urban theologians by whom he wassurrounded was to measure out the space required inthe streets and sidewalks by the people and cars gen-erated by 5-, 10- and 20-storey buildings on an iden-tical site. The interrelationship of measurable factorsis again clearly demonstrated. But one of Unwin’smost forceful contributions to theory is his recogni-tion of the fact that ‘the area of a circle is increasednot in the direct proportion to the distance to betravelled from the centre to the circumference, but inproportion to the square of that distance’. Unwinused this geometrical principle to make a neat pointabout commuting time: as the population increasesround the perimeter of a town, the commuting timeis not increased in direct proportion to this.

The importance of this geometrical principle isprofound. Unwin did not pursue its implications. Hewas too concerned to make his limited point aboutlow density. But suppose this proposition is subjectedto close examination. The principle is demonstrated

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FIGURE 8.4Change in the scale of the grid. Le Corbusier’sproposals for dwellings with setbacks (from hisproposals for a city for 3 million people) aresuperimposed on the Manhattan grid and open upnew possibilities in the building form.

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again in Fresnel’s diagram (Fig. 8.5) in which eachsuccessive annular ring diminishes in width but hasexactly the same area as its predecessor. The outerband in the square form of this diagram has exactlythe same area as the central square. And this lies atthe root of our understanding of an important prin-ciple in relation to the way in which buildings areplaced on the land.

Suppose now that the central square and theouter annulus of the Fresnel diagram are consideredas two possible ways of placing the same amount offloor space on the same site area: at once it is clearthat the two buildings so arranged would posetotally different questions of access, of how the freespace is distributed around them and what naturallighting and view the rooms within them mighthave. By this process a number of parameters havebeen defined which need to be considered in any

theoretical attempt to understand land use bybuildings.

This central square (which can be called thepavilion) and the outer annulus (which can be calledthe court) are two ways of placing building on theland. Let us now extend this. On any large site adevelopment covering 50% of the site could beplotted as forty-nine pavilions, as shown in Fig. 8.6,and exactly the same site cover can be plotted incourt form. A contrast in the ground space availableand the use that can be made of it is at once appar-ent. But this contrast can be extended further: theforty-nine pavilions can be plotted in a form whichis closer to that which they would assume as build-ings (that is low slab with a tower form over this).This can now be compared with its antiform: the same floor space planned as courts (Fig. 8.7). Thecomparison must be exact; the same site area, thesame volume of building, the same internal depthof room. And when this is done we find that theantiform places the same amount of floor space intobuildings which are exactly one third the total heightof those in pavilion form (Martin and March 1966).

This brings the argument directly back to the ques-tion of the grid and its influence on the buildingform. Let us think of New York. The grid is develop-ing a certain form: the tall building. The land mayappear to be thoroughly used. Consider an area ofthe city. Seen on plan there is an absolutely evenpattern of rectangular sites. Now assume that everyone of those sites is completely occupied by a build-ing: and that all these buildings have the sametower form and are twenty-one storeys in height.That would undoubtedly look like a pretty full occu-pation of the land. But if the size of the road netwere to be enlarged by omitting some of the crossstreets, a new building form is possible. Exactly theFIGURE 8.5

FIGURE 8.6

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same amount of floor space that was contained inthe towers can be arranged in another form. If thisfloor space is placed in buildings around the edgesof our enlarged grid then the same quantity of floorspace that was contained in the 21-storey towersnow needs only 7-storey buildings. And large openspaces are left at the centre.

Let us be more specific. If the area bounded byPark Avenue and Eighth Avenue, and between 42ndand 57th Street is used as a base and the whole areawere developed in the form of Seagram buildings36 storeys high, this would certainly open up someground space along the streets. If, however, theSeagram buildings were replaced by court forms(Fig. 8.8) then this type of development while usingthe same built volume would produce buildingsonly 8 storeys high. But the courts thus providedwould be roughly equivalent in area to Washington

Square: and there could be 28 Washington Squaresin this total area. Within squares of this size therecould be large trees, perhaps some housing, andother buildings such as schools.

Of course no one may want this alternative. But itis important to know that the possibility exists, andthat, when high buildings and their skyline are beingdescribed, the talk is precisely about this and notabout the best way of putting built space on toground space. The alternative form of courts, taken inthis test, is not a universal panacea. It suggests analternative which would at once raise far-reachingquestions. For instance, the open space provided inthe present block-by-block (or pavilion) form is simplya series of traffic corridors. In the court form, it couldbecome traffic-free courts. In this situation the ques-tion which needs answering is: at what point do wecease to define a built area by streets and corridors? At

FIGURE 8.7

FIGURE 8.8

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what point could we regard a larger area as a traffic-free room surrounded by external traffic routes?

In all this the attempt has been simply to give ademonstration of procedure. The full repercussionsof the questions are not obvious. They are highlycomplicated. But the factual aspect of the studyestablishes a better position from which to under-stand the nature of the complication and the limitsof historical assumptions. What is left is somethingthat can be built upon and needed decisions arebrought back to the problem of the built form of anurban area not merely of a building. Here, thechoice of the built form is critical in a number ofways, not least as a means of securing a new unityof conception.

Take for instance the question of the size of theroad net. Professor Buchanan has looked at thisfrom another angle (Ministry of Transport, 1963).Looking at cities in relation to traffic, he saw thatmost of them are built up from a collection of local-ities. He called these ‘environmental areas’. Theseareas are recognisable working units. They are areasin which a pattern of related uses holds together:local housing, shopping, schools, etc., would be oneobvious example. These areas are recognisable inManhattan just as clearly as they are in London.They form, in Professor Buchanan’s terms, ‘the roomsof a town’. They need to be served by roads butthey are destroyed when roads penetrate and sub-divide them. His solution was to try to recogniseand define these working areas and to place the netof roads in the cracks between them. By estimatingthe amount of traffic that might be generated bythe buildings in such areas, Professor Buchanan wasable to suggest some possible sizes for the networks.He had in fact by this procedure redefined the gridof a town in terms of modern traffic.

Here then is a proposition for a framework withinwhich we can test out some possible arrangementsof the built form. Professor Buchanan selected St Marylebone as one of his test areas. This happensto adjoin the main London University site (alreadydefined as a precinct in the London Plan) and this inturn is contiguous with the area around theFoundling Estate which has been used in someCambridge studies of the built form (Fig. 8.9). Allthree areas are approximately equal in size. TheFoundling area (bounded on the north and southby Euston Road and Theobalds Road, and on thewest and east by Woburn Place and Grays InnRoad), is about 3700 ft from north to south and2000 ft wide. It developed a cohesion of its own.How did this happen?

This in turn can be related back to the main lineof argument. In 1787 the whole of this area con-sisted of open fields: there were no controlling fea-tures. A plan of 1790 divides the land into buildingplots by its network of streets and squares. The sub-sequent history, so well traced by Olsen (1964),shows the development and elaboration within thispattern. By 1900 the area could have been describedby the language that Mrs Jacobs applies to GreenwichVillage. The intellectuals were there: so were theworking Londoners: so were the Italians aroundtheir hospital in Queen Square. There were hand-some houses; tenements and mews; hotels andboarding houses. The area had its own Undergroundstation and its own shopping area along MarchmontStreet. It served a complex community.

By 1960 the balance within the original patternhad radically altered. Fast moving traffic using thesmall scale grid of streets had subdivided the area.Site by site residential development at a zoned den-sity of 136 people to the acre produces only oneanswer: tall blocks of flats. Redevelopment of sitesfor offices created taller and thicker buildings. Thehospitals, which needed to expand, were hemmed inby surrounding development. The pattern congealed.

In this situation only a new framework can openup a free development. And if Professor Buchanan’ssurrounding road net is accepted as a basis for thedevelopment of the environmental area, the problem

FIGURE 8.9Environmental areas and road networks as suggestedby Buchanan.

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can be seen within a new unifying context. What sortof advantages could a rearrangement of the builtform now create? Professor Buchanan in his studyarea outlined three possible solutions with progres-sive standards of improvement. The merit of this isthat it sets out a comparative basis of assessment. Buteven his partial solution leads to an extensive roadand parking system at ground level. From the pointof view of the pedestrian the position is made toler-able by the use of a deck system to create a secondlevel. Above this again, some comparatively tallbuildings are required to rehouse the built space thatis at present on the ground. This kind of image of thearchitecture of cities has a considerable history inmodern architecture and has been much used as anillustration of central area reconstruction. But, asProfessor Buchanan himself asks, what building com-plications does it produce and what sort of an envi-ronment does it create? Is it in fact worth building?

Professor Buchanan’s range of choices could infact be extended by applying some of the theoreticalwork which has been described. And when this isdone the results are significantly different. Theboundaries of the total area that are being consid-ered have been defined by this new scale of the

road network: the grid. Within this, the existingfloor space can be assessed (Fig. 8.10): 34% of thesite is occupied by housing: 25% by roads: 15% byoffice and commercial use: 12% is open space. Inaddition there is an important shopping street, amajor hospital and several schools and educationalbuildings. With this information available it can beconsidered at a theoretical level how this might bedisposed in a new building arrangement.

First, the shopping street, Marchmont Street,could be established as a north/south pedestrianroute associated with the Underground and somehousing. If all the office space which is at presentscattered throughout the area could be placed in asingle line of buildings around the perimeter of thearea (where some of it already is), it need be nohigher than eight storeys. All the housing at presentin the area could be placed within another band ofbuildings sited inside this and no higher than fivestoreys. Of course it could be arranged on theground to include other forms and types of hous-ing. But in theory, the bulk of the building at pres-ent covering the area could be placed in two singlebands of building running around its edge, leavingthe centre open, which would be a park-like area

FIGURE 8.10aQuantities of built and open space in the Foundling Area.FIGURE 8.10bPossible geometric layout of the same quantities of built space in perimeter form.

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about the same size as St James’s Park (Fig. 8.11).Precisely the same amount of floor space wouldhave been accommodated. There need be no tallbuildings, unless they are specifically wanted. Allthe housing could look onto a park. Buildings suchas schools could stand freely within this. Therewould be a free site and a park-like setting for newhospital buildings.

All that may sound theoretical and abstract. Butto know what is theoretically possible is to allowwider scope for decisions and objectives. We canchoose. We can accept the grid of streets as it is. Inthat case we can never avoid the constant pressureon the land. Housing will be increasingly in tall flats.Hospitals will have no adequate space for expan-sion. Historic areas will be eaten into by new building.

A total area once unified by use will be increasinglysubdivided by traffic. We can leave things as theyare and call development organic growth, or wecan accept a new theoretical framework as an out-line of the general rules of the game and worktowards this. We shall know that the land we needis there if we use it effectively. We can modify thetheoretical frame to respect historic areas and elab-orate it as we build. And we shall also know that theoverlapping needs of living in an area have beenseen as a whole and that there will be new possibil-ities and choices for the future.

FIGURE 8.11aThe existing plot layout and building development inan area of London that might be regarded as anenvironmental room. But it is subdivided by roadsand the limited size of the building plot increasinglyforces development upward.

FIGURE 8.11bThe same area as that in 8.11a. The road network is now enlarged and runs around the boundary of the area. Theoretically an entirely new disposition of buildings is possible and the illustration showsexactly the same amount of floor space in a newform. Tall buildings are no longer necessary: thebuildings themselves have a new freedom fordevelopment and a considerable area of open space is discovered.

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Olsen, D. J. (1964). Town Planning in London, Yale UniversityPress.

Reps, J. W. (1965). The Making of Urban America, PrincetonUniversity Press.

Robinson, C. M. (1916). City Planning, Putnam.Sitte, Camillo (1889). City Planning According to Artistic

Principles, translated by Collins, G. R. and C. C. (1965).Phaidon Press.

Unwin, R. (1912). Nothing to be Gained by Overcrowding,in Creese, W. L., ed., 1967, The Legacy of RaymondUnwin: A Human Pattern for Planning, MIT Press(Cambridge, Massachusetts).

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Source and copyright

This chapter was published in its original form as:

Martin, L. (1972), ‘The Grid as Generator’, in Martin, L. &March, L. (1972) (editors), Urban Space and Structures,Cambridge University Press, Cambridge, 6–27.

Cambridge University Press, reproduced with permis-sion from the author and publisher.

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