Tag Archives: public space

A conversation about the geometry of nowhere

In response to my last article, Bruce Liedstrand of Community Design Strategies in Paris writes,

I read with interest your essay on The Geometry of Nowhere because I divide my time between Paris and Silicon Valley (the site of your Cupertino Target store example). After re-reading the essay, I am puzzled. I hear your frustration with narrow sidewalks, but I am lost in understanding your concept of “place”.

My experience has been that a “place” is created by spatial enclosure, the use of adjacent buildings to enclose and shape the space into a comfortable “place”.  Paris is strong on spatial enclosure. To me it seems almost as if Paris started as a solid mass and that the boulevards were carved out of the mass by broad blades and the narrower streets (“rues”) by finer blades. Wherever I am in Paris I feel comfortably inside a good place.

Your essay seems to indicate that “place” exists without any enclosure by buildings. That, indeed, it can exist on the outside edge of buildings rather than inside a group of buildings. Is that what you intend?

I am puzzled also by your discussion of the Cupertino Target store, which I have personally visited. (Ed note: What are the odds?) When I look at your illustration of your changes, I don’t see any “place”. What I see new is open spaces outside buildings from which cars have apparently been excluded. Do you intend to say that exclusion of cars is the key to converting undifferentiated open space into a good “place”? What is it about these new open spaces around the store that would make them comfortable for people to linger in?

Perhaps I am reading your essay wrong? Can you please point me in the right direction?

Thanks.

Enclosure creates a room, but it’s not sufficient to create a place. You can see this in Paris, where some of the best places in the city are not enclosed, for example along the Seine, or the Luxembourg garden. And the most enclosed places, like Place Vendôme, are not very interesting.

To get a good understanding of the relative impact of enclosure and open space on place, all we have to do is take a long walk along the axe historique. Start at Place de la Concorde, which was about 50% sidewalk 50% free space when it was created and is not enclosed. All the free space was converted to road and now it is perilous to get across, but still a place. Walk down to Rond-Point de l’Élysée through a wood with substantial open space to walk across. I don’t know if that counts as enclosure, but it’s a good place. Then you have the model of place, the Avenue des Champs-Élysées with its straight-aligned buildings, that is also a place with 50% sidewalk and 50% road. And it is a major road, 10 lanes of traffic, but that doesn’t really interfere with it as a place because there is little reason to cross the road, and it can be done in two steps thanks to traffic islands.

Once you’re up the hill and you go across the monster Place de l’Étoile (horrible place, all cars driving maniacally so that pedestrians have to cross in underground passages), you end up on Avenue de la Grande Armée, which is morphologically identical to the previous avenue except that some of its space is taken by parking lots. That means the ratio of sidewalk to road is much less than 50/50. It’s also much less crowded and much less attractive than the previous avenue, but it still works.

After you get across Porte Maillot to Avenue Charles de Gaulle in Neuilly, then you find the same buildings with the same alignments and the same enclosure as the two previous avenues, except this time the space has been traffic-engineered to hell, combined with speed cameras to dissuade speeding. What space there was on Grande Armée has been cut even further, and the result is a dead street on what is a major business center of the city.

Finally cross the bridge and climb your way up to the Parvis de La Défense, where you will find that the buildings are modern and completely random, but the space is fully open to people and always full of people. (Even on Sundays!) I interviewed the master planner for the northern expansion, and he said the developer of La Défense did not agree to build the 25m wide pedestrian bridge he had designed to connect the site to the main place. After their small “passerelle” failed they backed down and built the full bridge, and it works, always full of people.

So there you have it, the closest thing to a controlled experiment on place and enclosure. Enclosure turns out to be irrelevant.

Have a nice walk.

Do you really find La Defense a pleasant place?  For me, it is utterly placeless – one of the worst locations in Paris?

If you have extra time on a pleasant afternoon, would you really rather spend it sitting in the open space of La Defense than in my neighborhood park?

p1010675_4

La Défense is a business place, and it works at what it is. But compared to Avenue Charles de Gaulle, which is another business place, and which has the same architecture and alignments as the rest of Paris, it is a much better place.

Can you say this is not a good place?

Look at all the people. They’re not locked up in their offices. The neighborhood is set up so you can go straight to your office to the metro using tunnels, but when I was there I always preferred taking a detour on the surface. Take my word for it, people even go there on the weekends to teach their kids how to ride bikes and roller-skate. They don’t care that the buildings aren’t aligned.

What I am asking with my article is how can we reduce and remove sprawl without going through an expensive process of total demolition for which we won’t have the money anymore? We don’t have the choice of your small neighborhood park. A place and a park are very different things anyway. Cities existed for centuries without parks, but never without place. If we reintroduce place in sprawl cities, that means shops that rely on place to survive don’t have to open up in the mall anymore, they can do business anywhere because the entire city is a mall (one of the first things I realized about Paris). Then your city starts to grow around place instead of around roads, and people have a reason to linger.

Yes, for me it is not at all a good place in the photo or in personal experience.  People are dwarfed by the size of the space (in the photo, the space is almost empty) and it is not comfortable.  One can look at the buildings as perhaps interesting objects, depending on one’s taste, but it certainly is not a place I would linger in or return to regularly if I didn’t work there.Let’s accept that we disagree, vigorously, about whether La Defense is a good place.  But what, in your view, makes a good place.  So far I hear you favor an absence of cars and openness?  Is that right?  Is that all, or can you tell me more?

And what would be good about your redesigned Target store?

I didn’t redesign the Target store, I left it there as a necessity of the context, and the people at La Défense aren’t looking at the buildings. They’re a necessary part of the décor, but they’re not the reason people use the place, or any place.La Défense became a success, despite everyone’s intent, because economic conditions forced the developers to break the master plan and allow any random building to be built. Had they not done so it would be exactly like Empire State Plaza in Albany. The difference between the two is not architectural, it is socio-economic.

You do not need to remove cars to make a good place, you only need to remove the exclusivity for cars. What makes a good place is total freedom of movement for everyone, including the freedom to stop and linger. You can’t do that in traffic engineered space because you are confined between very narrow limits. They tell you how fast to go, when to stop, where to turn, it’s a nightmare, but one that we put up with to go fast.

Is an empty space out in the desert a good place because everyone can move freely?  Or are you talking about places within cities?  Is it just traffic engineered spaces that you reject?  Are you advocating a Hans Monderman approach to streets?  Are you rebelling against “confinement”, or is some broader principle involved?

I agree that the Empire State Plaza in Albany is a terrible place.  Are you saying that the only problem with it is that, unlike La Defense, the buildings are not place at random?  What do you mean by saying that the difference is “social-economic”?

Could you please write in one paragraph what you believe are the key factors in creating a good place within a city so I can understand where we might agree or disagree?

Deserts can make a good place, although there is not much desert urbanization. (Desert driving is a lot of fun nevertheless.) Open space alone does not make a place, you also need people there, and the reason that people go through any place is to participate in and generate social and economic networks. This was not done at Empire State Plaza but was done at La Défense.

The issue is at core about freedom. How much freedom of movement do I enjoy, how much freedom to grow and build do I enjoy? In a place you can walk anywhere and build anything anywhere, or just occupy the space to conduct some activity like playing hockey or learning to ride a bike. That creates networks and attracts people. In sprawl the entire space is traffic engineered. To move around you are practically on a conveyor belt, offered only a linear path, delimited speed and a select few choices. You can’t build anything because of the zoning. The choices available to you have been selected by the traffic engineers and the planners, and they only fit  their model of what they want you to do. There is no creativity possible to invent your own journey. A famous game designer once said “a game is a series of interesting choices.” What kind of choices does sprawl offer?

The one place in sprawl where people are given a shred of creativity is the mall, and that’s how people who live in sprawl spend their free time. You can go there and just hang out, inventing an activity from nothing. It’s all the place they have left.

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The movement economies

Bill Hillier of Space Syntax is, along with Christopher Alexander and Michael Batty, part of the British old school of urban complexity researchers. (Hillier has joked that he would have used the term “Pattern Language” instead of Space Syntax had Alexander not used it first.) He has studied the functional impact of spatial relationships on human behavior over a career spanning several decades, and came upon some very insightful results. The synthesis of his career was published last year in the book Space is the Machine, which you can read here.

Hillier presents a theory of urban emergence founded upon two ideas. First, that circulation in a city is determined by the configuration of lines into a global hierarchy of depth, which he calls integration. Second, that activities in the city adapt to take maximum advantage of this movement, a phenomenon he calls a “movement economy.”

How did he draw this conclusion? By observing that integration of lines could predict where all the major shopping streets in London are.

Which then is primary? Let us argue this through the spatial distribution of retail, the commonest non-residential land use. We may already have been suspected of having confused the effects of spatial configuration on movement with the effect of shops. Are not the shops the main attractors of movement? And do they not lie on the main integrators? This is of course true. But it does not undermine what is being said about the structure of the grid as the prime determinant of movement. On the contrary it makes the argument far more powerful. Both the shops and the people are found on main integrators, but the question is: why are the shops there? The presence of shops can attract people but they cannot change the integration value of a line, since this is purely a spatial measure of the position of the line in the grid. It can only be that the shops were selectively located on integrating lines, and this must be because they are the lines which naturally carry the most movement. So, far from explaining away the relation between grid structure and movement by pointing to the shops, we have explained the location
of the shops by pointing to the relation between grid and movement.
(SITM 125)

Once it has been demonstrated that it is the global network structure that determines where most of the movement will go, not any particular destination, then what remains to do is to exploit this movement. This is the movement economy. It is, in one sense or another, behind every act of urbanism, operating at every scale.

Every trip in an urban system has three elements: an origin, a destination, and the series of spaces that are passed through on the way from one to the other. We can think of passage through these spaces as the by-product of going from a to b. We already know that this byproduct, when taken at the aggregate level, is determined by the structure of the grid, even if the location of all the a’s and b’s is not.

Location in the grid therefore has a crucial effect. It either increases or diminishes the degree to which movement by-product is available as potential contact. As we saw in the coloured-up maps, this applies not only to individual lines, but to the groups of lines that make up local areas. Thus there will be more integrating and less integrating areas, depending on how the internal structure of the area is married into the larger-scale structure of the grid, and this will mean also areas with more by-product and areas with less.

Now if cities are, as they were always said to be, ‘mechanisms for generating contact’, then this means that some locations have more potential than others because they have more by-product and this will depend on the structure of the grid and how they relate to it. Such locations will therefore tend to have higher densities of development to take advantage of this, and higher densities will in turn have a multiplier effect. This will in turn attract new buildings and uses, to take advantage of the multiplier effect. It is this positive feedback loop built on a foundation of the relation between the grid structure and movement this gives rise to the urban buzz, which we prefer to be romantic or mystical about, but which arises from the co-incidence in certain locations of large numbers of different activities involving people going about their business in different ways. (SITM 126)

From this knowledge, we can arrive at a paradigmatic definition of urbanity. A space can be considered urban if it makes maximum economy of the movement that passes through it. A city, at any scale, will be qualified as a good city if the experience of movement is not felt as a burden but as an opportunity and pleasure.

A visitor from Canada once remarked to me that he had walked from the Eiffel tower to the Pantheon, a trip of more than 4 kilometers, without feeling the distance. This is something he could never have done back home, where inevitably one would run into long stretches of mind-numbing repetition or parking lots. Paris, on the other hand, offered him a path through the city that was rewarding his presence. Certainly the excellent late 19th-century residential architecture plays a role in creating a basic comfort level, but architecture alone does not distract for such a long distance.

Paris is known as a city of highly sophisticated urbanity, and this is attributable to the efficient movement economy that was seeded there during the Haussmannian period. The most integrated lines, the typical boulevards and avenues, have been constructed in such a way that they make maximum use of residual movement. And what may be most surprising, a revelation that the occasional tourist will miss out on, is that the least integrated lines, the common residential streets, are generally quite boring, bordering on unpleasant. They are rarely seen by anyone except their residents due to their spatial segregation. It is safe to say, then, that the “real” Paris, what makes the city worth visiting, are its highly integrated spaces.

How do these spaces realize movement economies? Firstly they provide multiple scales of movement as well as the interfaces between those scales of movement. The grand avenues centered on the Arc de Triomphe are in fact three different scales of movement: promenade, street and highway, connecting into each other. While someone crossing the city in an automobile would be exposed to all the activity taking place on the promenades, he could decide to pull over into the street section, curb-separated from the highway section, and park his car in an available spot, then walk to his chosen destination. While walking there, he encounters shops he could stop in if it occurred to him to make a purchase. Restaurants and fast-food outlets provide him with a convenient option for dining. On the street side, news kiosks offer him information and headlines. All of this benefits him and occupies his mind at no cost as he was already taking this path for other reasons.

While he is walking to his destination, people are sitting in sidewalk terraces drinking beer and coffee, watching him walk by. They are also taking advantage of movement. William H. Whyte, author of the classic The Social Life of Small Urban Spaces, observed that the primary activity that takes place in plazas is people-watching, people moving through that is. On the Avenue des Champs-Élysées, the most trafficked in the city, restaurants have outdoor dining rooms right between the highway and the pedestrian flow. They are highly prized, despite the noise and wind, because people enjoy watching the movement.

Since Alphand, the city of Paris has split promenades into three strips. The center strip is the open space through which pedestrians walk. The street-side strip is for street furniture such as kiosks, public washrooms, benches, bus stops, and so on. The building-side strip is for “concessionaires”, retailers and restaurants renting a part of the street to open their space to the exterior. The formula for a good promenade is that simple.

Needless to say, it takes quite a lot of movement to support so many mutually-dependent activities. But high-end avenues are not the only spaces that can take advantage of movement economies. Urban movement is fractal (it occurs at all scales). Hillier found that placing a limit on the range of movement, one obtained a local integration map that was different than the global integration map, and the movement in this locally integrated space was qualitatively different than global movement. These locally integrated paths develop local movement economies of their own. Typically, while highly integrated paths will become high-end shopping streets, locally integrated paths will be neighborhood service streets. Instead of trendy restaurants, fashion boutiques and cinemas, you find supermarkets, bakeries, post offices and cafes. And when we look at things with enough abstraction, we can see that even a shopping mall is a form of locally-integrated movement economy, where anchors terminate important axis and boutiques support each other by intercepting movement. Kiosks and cafes now take up even more space in the center of shopping mall promenades than they do in Parisian boulevards. It should be no surprise that people who live in suburban cities reflexively head to the mall for activity. Shopping malls, in the suburbs, have the most densely developed movement economies!

Besides creating commercial potential, movement economies also provide security. This is something that Jane Jacobs insisted on in Death and Life of Great American Cities through her concept of eyes on the street, but Hillier found an inverse statistical correlation between burglaries and spatial integration. What this brings us to is that there is a lower bound to urbanity, that we have defined as the realization of movement economies, where spaces lose integration and become segregated. If there is not enough movement, there is no purpose to public space. This is the point where public space becomes pathological, and where “defensible space” becomes necessary. Disastrous social housing projects have become the textbook case for failed public space, and their segregation explains their pathologies.

Parisian urbanism offers another excellent solution out of this problem. While the avenues are congested and noisy, full of life and activity, the lots are organized as courtyards from which several buildings are accessible. These courtyards are locked behind digitally-secured coach doors. It is rarely the case that one is invited to a dinner party without being given several “digicodes” to get through the secured, segregated spaces. Once in the courtyard, the noisy street becomes peaceful silence. These courtyards are functionally identical to the despised suburban cul-de-sac. But the cul-de-sac is not the problem, the streets they connect to are the problem. Paris balances two extremes, highly public, highly integrated space and completely private, gated space, side-by-side, supporting each other. Manhattan’s street-and-skyscraper urbanism is essentially the same, except that instead of going deep away from the street, one has to go up after entering segregated space.

New Urbanists in America and compact city advocates in Europe insist on having fully open grids, sometimes with alleys, instead of cul-de-sacs. There is nothing wrong with a cul-de-sac in itself; it is only a large residential building turned on its side. The important work is creating density in highly integrated lines. Arturo Soria y Mata invented the linear city in the 19th century as a utopia, but in reality, all cities are linear cities, functioning at fractal scales. The realization that the spatial integrity of the line is more important than anything that goes on behind the buildings occurred to me while taking a bus through the west Paris city of Nanterre, widely acknowledged to be a wasteland. The line the bus was taking was well composed, and I did not realize where I was until I caught a glimpse of wasteland Nanterre in a gap between two buildings. So far as anyone on that street was concerned, this didn’t affect them negatively. That is how resilient urban fabric can be.

Afterword

Local integration map of Central London

From Space is the Machine, global and local integration maps of Central London.

Self-organization of cities around natural movement is an important demonstration of complexity. Without anyone having willed or designed it that way, the aggregate actions of the millions of residents of London, all randomly travelling from one point to another of the network, resulted in the production of a fractal structure of the urban grid.

References

Bill Hillier. Space is the Machine
New Science. New Urbanism. New Architecture – Proceedings from a London conference, Katarxis.

A measure of urban connection

What does it mean for a city to be connected? And is there quality resulting from this property? Let’s define the basic node of a city as a doorway. (Not necessarily a building. A single building can have many doorways to separate spaces.) A connection is the distance from this doorway to the next node, that is to say the next doorway. A well connected city is a city where the distance from doorway to doorway is minimized, since everything will be easily accessible from the public space.

Shopping malls have mastered this aspect of cities. They tightly connect boutiques which are long and narrow together, and place large stores at terminating vistas such that their bulk does not create a connective void. They have even restored the practice of kiosks, placing them in the largely unused central width of their interior street. Every effort is made to prevent holes from closed-down stores. Mall operators have found that when people run into such an absence of connection, they turn around, making a chunk of the mall unattractive and isolated. Since the mall exists to allow separate shops to benefit from each other’s proximity, it is terrible business to have such a hole in the network.

The concept of the suburban shopping mall is a reactionary invention. When urban planners defined the new city as being strictly automobile-based, some clever businessmen found it worthwile to restore the city street as an enclosed megabuilding, (what Leon Krier would call a landscraper) offering the connective value of the traditional city to otherwise stranded suburbanites. And the only way they could slip it by the planning authorities was to wrap it around a massive shell of parking. As such, although the mall’s interior street is an extremely well connected public space, once you exit that street the measure of connection drops close to zero. While you can walk in the mall from one doorway to another in a few seconds, to reach another doorway after leaving the mall may well take several minutes. (And you’ll almost certainly need to take your car.)

The most basic thing a city can do to build connections is create sidewalks from doorway to doorway. Humans move on foot. Everything else is just a shortcut.