Location, location, location and the value of urban place

13 Sep 2018

Alan Penn, Professor of Architectural and Urban Computing at UCL, outlines why the meaning of a place, as much as its location, should be considered when urban planning

This essay is one of a collection of articles created by Lendlease and the Centre For London, written by a selection of built environment experts. These thought-provoking commentaries explore the great power and great responsibility that comes with placemaking – and how to create a city space that enhances the wellbeing of everyone who experiences it.

You can read the other articles in the series here.

The concept of ‘place’ comprises at least two main components: location and context. The first has often been taken as a proxy for how close or far away one is from the city centre. The second covers a multitude of different qualitative factors that it seems ought to be important in defining the way urban neighbourhoods function.

In this essay I argue that an essential component of placemaking lies in the way that urban space becomes meaningful to people, and so makes the world intelligible, creating the conditions in which we can act purposefully as members of society. In order to make this argument I review a body of recent work that has tried to uncover the way that urban placemaking and neighbourhood configuration contribute to the social life of cities, and how this might affect value.

The value of urban place

It is a truism that, aside from size, the value of a property is determined by location. Early theories in geography held that what mattered was distance from the city centre: however, a cursory review of the evidence suggests that the process must be more complex.

Cities tend not to be characterised by concentric rings of similar value. They often show a north-south (e.g. Manchester) or an east-west (London) division in values. Run-down inner city estates sit cheek by jowl with gentrified middle-class areas, and some of the most expensive residential streets are in the outer fringe of the suburbs. While one street in the city centre may be dominated by high-value retail, a turn of the corner is likely to be associated with a different retail mix at a lower rental, while yet another turn will take one into a completely different land-use class, and so into a different sub-market in property.

Two different drivers of value for property have generally been proposed. Either value is taken to be determined primarily by utilitarian factors, such as size of property, or distance to a market centre; alternatively, analysis of so-called ‘hedonic variables’ allows one to consider those factors that contribute to value based on human pleasure: the sunnier garden or the better view.

In general terms, neither approach has so far considered in any detail the street layout of urban neighbourhoods. This has recently been subject to several studies which make use of methods of spatial analysis to represent and quantify the network properties of the streets in a neighbourhood.

While we all understand intuitively the difference between ‘main streets’ and ‘back streets’, the idea that these properties might be generalised through formal description and analysis is relatively recent. By representing every street segment in a neighbourhood as a node in a network, connected to those street segments each links to, and weighting the strength of connection according to change of direction (the more straight ahead, the stronger the connection), the representation captures the geometry with enough detail to allow comparison of differently designed areas. This allows quantitative analysis to be used where previously only qualitative methods had been possible.

Alain Chiaradia and Bill Hillier, for example, investigated the value that might be associated with street network effects that could be shown to reduce or increase vulnerability to burglary. First they showed that there appears to be a systematic increase in crime vulnerability associated with certain types of street network configuration, and then they used Home Office data on the cost of crime to define the inherent value of neighbourhoods designed to reduce crime.

Hillier expanded considerably on this analysis to investigate economic factors in urban configuration. He found that value of high streets is best correlated with measures of network ‘betweenness’, while that of residential property as measured by community tax band is best associated with ‘closeness centrality’. He suggested that this reflects the dependence of retail upon passing trade (something indexed by the degree to which a street segment lies on many different routes ‘between’ other origins and destinations in an area), and value of residence on accessibility in the local area (indexed instead by how ‘close’ a street segment is to all others in an area).

An important element of the complexity of urban property markets depends upon the way that single sites may be subject to different markets for different land uses. In early geographic studies, a simplifying assumption was made that ‘as the crow flies’ distance to the CBD could account for the cost of transportation – of people from home to work, or of goods to a market – and that these in turn would account for the distribution of land uses in the city.

However, Laura Narvaez, in a recent comprehensive study of property markets in the city of Cardiff, introduces street networks and distance travelled on them into an analysis of these markets. Her analysis, far from showing the simple trade-offs assumed by economist William Alonso, found much more subtle and varied patterns.

More recently, Stephen Law’s hedonic analysis of London residential prices, including street network configuration as hedonic variables, found these to be implicated in markets, as Hillier had suggested, in terms of the local accessibility of a given location. However, he also found that distinct local sub-markets exist, many with estate agents’ names, and that sometimes these sub-market areas can be identifed within the street network using a method of ‘community detection’ adapted from social network analysis. Community detection methods identify those nodes in a network that are more strongly interconnected amongst themselves than they are to surrounding nodes.

The concept of ‘place’

Place has taken on a new importance in discussions of urban value over recent years. Architects, urban designers and planners now style themselves as ‘placemakers’, while the ills of the anonymous modern city have been ascribed to a failure to create places that people find meaningful.

Despite its new popularity, the concept itself is complex and multi-faceted. Melvin Webber described the importance of place in contrast to those aspects of society that seem to overcome space and allow a community to cohere at a distance across the “non-place urban realm”. Environmental psychology describes ‘place attachment’ as an emotional tie experienced by individuals for their home or local neighbourhood.

Bill Hillier and colleagues proposed a mechanism through which the spatial and the social can be considered as a single phenomenon. As people move through and experience urban space, their movement gives rise to a probability of encounter with others. This, Hillier suggests, creates a “virtual community” which is only realised when co-presence leads to interaction, communication or transaction.

The probability of any given association between individuals or different categories of people depends first and foremost on their repeated movements through urban space, a product in turn of locations of different land uses, the configuration of the street network, the regularities of human daily life and the patterns of co-presence that all these create.

Place considered in this way can be seen at once to cover the individual, the socioeconomic and the physical/spatial construction of the city. The complexity of these associations is therefore intrinsic to the valuation of the urban realm, as are the ways in which they can be simplified enough to be learned and made meaningful to people.

I propose a possible process through which distributions of space and social function in cities could emerge over time, and suggest how this pattern can become meaningful. The process is intrinsically related to value, since value is established in a market and so captures the opinions of many different actors, each of whom assess the positive and negative externalities of any specific site for their own purposes. Amongst these are the decisions of other actors who, as neighbours and passersby, will produce positive or negative effects on the site in question.

The result of the operation of this kind of market over time is a distribution of land uses in which there is a high degree of spatial autocorrelation. In other words, the functional use of a building cannot be considered as completely independent from that of its neighbours, nor they from theirs in turn across a whole neighbourhood.

In this way, and in the absence of regulation such as land use planning controls, a market will evolve to distribute land uses in a way that takes advantage of the spatial affordances of the street network, such as local or large-scale accessibility, as well as the positive and negative externalities of neighbouring land uses. It is this set of correlations between spatial configuration, functional land use and patterns of traffic and occupancy, and their direct relationship to the social, cultural and economic processes which influence their evolution over time, which provides a basis for urban places to be thought of as meaningful.

If these processes lead to spatially correlated patterns, it should be possible to retrieve from the urban realm information about the social processes that produced it. It should also be possible, by learning these patterns of association, to predict the likelihood of other patterns: to gain information from the physical and spatial fabric of the city, for example, about the virtual community, and so to inform one’s own decisions as a social agent.

This process plays a central role in creating the conditions in which people have autonomy, and it is here that the real value of urban place lies. It lets the shopper, for example, predict where best to look for a specific class of goods; or the shop-owner predict where best to set up store to catch passing trade or benefit from the attractive effect of a cluster of similar shops.

When placemaking fails, the result is to interrupt the patterned relationships between different aspects of the urban environment. In doing so we reduce the urban realm to a pattern of meaningless associations, and so deny people the ability to act intentionally as social agents, depriving them of their right to self-determination. And this is, as Doyal and Gough argue, must be classed as the most fundamental of human rights.

 


This article was written by [Alan Penn] (“Author”) (independent of Lendlease) and originally published by the [Centre for London]. The opinions, views and representations expressed in the article are those of the Author. Lendlease has not independently verified any of the information in the article nor sought to confirm any underlying assumptions relied upon therein by the Author. Unless otherwise indicated, information contained in the article is current only as at the date it was originally published. Neither Lendlease, nor any member of the Lendlease Group, accepts any liability for any loss or damage suffered, howsoever arising, as a result of the use of any information in the article.