Resilient Urbanisms
From Landscape Urbanism to Green Infrastructure to Infrastructural Urbanism, each framework regards ecology as a primary tenet.

An ecological system's resilience is build up over time, yet can be undone in a brief moment.

This blog intends to share diverse perspectives on these evolving frameworks and to explore solutions to sustaining resilient urbanisms.

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FOLLOWING eca-scape
Measuring Fragmentation

The rigorous and systematic measurement of urban expansion or sprawl using satellite imagerya methodology that has recently become available and increasingly affordableshould also enable us to answer a number of important policy questions that are often raised in the literature:

1. To what extent is sprawl ubiquitous and universal rather than the result of particular land use policies in particular countries?

2. What is the relationship between sprawl as low-density development and sprawl as fragmentation?

3. Is urban fragmentation declining, stabilizing, or increasing over time?

4. Are vacant spaces left in the urban expansion process gradually being filled in, or is the presence of vacant land in the city footprint a more-or-less permanent feature of the urban landscape?

5. Should developing-country cities pursue similar urban expansion policies to those now being advocated in developed countries? and

6. Is sprawl likely to be reversed if transportation costs increase markedly and transportation externalitieslike congestion and pollutionare internalized?


Why should we be concerned with measuring the attributes of urban expansion orsprawl? From a scientific perspective, any phenomenon that humans observe and come to believe is of some importance to their lives merits precise measurement.

To quote Lord Kelvin (McHale, 145):
When you measure what you are speaking about and express it in numbers, you know something about it, but if you cannot express it in numbers your knowledge about it is of a meager and unsatisfactory kind.


Characterizing and Measuring Urban Sprawl

MEASURING URBAN SPRAWL AND COMPACTNESS: CASE STUDY ORLANDO, USA 

SIM S.(1), MESEV V.(

Characterizing and Measuring Urban Sprawl 

The literature characterizing sprawl is extensive including ―the scattering of urban settlements‖ (Harvey and Clark, 1971). Altshuler and Gomez-Ibanez (1993) describes sprawl as ―continuous low density residential development on the metropolitan fringe, ribbon low density development along major suburban highways, and development that leapfrogs past undeveloped land to leave a patchwork of developed and undeveloped tracts.‖ The term sprawl refers to a range from low-density urban development all the way to discontinuous and dispersed or even decentralized forms of urban expansion. At this point, it is important to review the most widely debated concerns and efforts to characterize sprawl as an urban form. 

First, many definitions describe sprawl as a development pattern that consumes more open space and produces more impervious area causing a less environmentally sustainable form compared to a compact development. A growing trend of smart growth suburb depicts new urbanism ideas for handling sprawl such as mixed-use zoning, pedestrian-friendly streets, transit, and town centers. The concern here is how to decide whether a tract of development is actually sprawl compared to compact development. Secondly, sprawl represents a stage in the development process. The EPA (2001) report notes, ―at a metropolitan scale, sprawl may be said to occur when the rate at which land is converted to non-agricultural uses exceeds the rate of population growth.‖ Therefore, sprawl should be considered in a space-time context, and not as a simple increase of urban lands (EPA, 2001). This suggests that sprawl should be measured on a development pattern continuum over time. Thirdly, many characteristics associated with sprawl relate to density either using population or housing data. Some studies (Barnes, 2001; Galster et al, 2001 and Harvey et al, 1971) suggested the expanded dimensions of sprawl such as continuity, concentration, clustering, centrality, nuclearity, mixed use and proximity. Finally, urban sprawl causes the loss of informal open space and wildlife habitats. Some of the fastest rates of loss have been occurring at the interface of urban core and rural areas at the metropolitan region. 

Developing a Measurable Definition of Compactness and Sprawl 

Despite a lack of rigorously defined idea of sprawl, the term is often defined by four land use characteristics: low density; scattered development (i.e. decentralized pattern); commercial strip development; and leapfrog development (Tsai et al, 2009). The last three characteristics are related to the spatial arrangement of the urban area. These phenomena often occur at a metropolitan area. In contrast to sprawl, compactness can be defined as more energy efficient and less polluting. Advocates claim that a compact development is more sustainable for economic, environmental and social dimensions. Ewing (1997) defined compactness as some concentration of employment and housing as well as a mixture of land uses. Galster et al (2001) defined compactness as the certain degree of clustered developments and measured it by the amount of land developed in each square mile. Tsai (2009) described compactness as often involving the concentration of development as apposed to sprawling development. There are similarity and differences of sprawl and compactness in terms of measurement of urban development at a metropolitan level. Hanson et al (2001) employ metrics to describe land development along six geographical dimensions: density; continuity; concentration; centrality; nuclearity; and diversity. Tsai (2009) used a set of four dimensions of metropolitan form - metropolitan size, density, degree of equal distribution and degree of clustering and utilized Moran, Geary, Gini, and Entropy indicators to measure those four dimensions for both population and employment distribution. With these issues in mind, six dimensions of sprawl indicators were selected.

Size: the urban land area which has often been used as a simple index of sprawl. The idea of using the urban land size for sprawl causes more land consumption than compact development. Because sprawl is characterized by an increase in the built-up area along the urban and rural fringe, this attribute gives considerable information for understanding the behavior of such sprawl. Larger urban size values indicate a greater degree of sprawl. 

Density: this can be measured by the population per unit of developed land. There are numerous density-based measurements that use population and employment data. Hasse (2004) suggested that density of new urbanization should be used as a measure of land consumption for new urban growth, Schneider et al (2009) used density of built-up land by measuring ratio of amount of urban land to all land by percentage. This index provided information on whether new land development is low or high density. Higher ratio of low-density development to total development indicates sprawl whereas lower rations indicate more compact or smarter growth patterns. In our study, the density indicator provides a measure of land consumption for new urban growth per capita. Population increment was calculated by comparing the difference between years from the following, 1974, 1985, 1993 and 2003. The amount of new urban growth in 1985, 1993 and 2003 was extracted from FWC land use and land cover maps and was then generated by intersecting urban areas in the earlier year. The new urban density indicator was calculated by normalizing the amount of new growth by the concurrent increase in population. Larger per capita new growth density values indicate a greater degree of sprawl. 

Continuity: The index of continuity is a measure of the size or the distance of newly developed areas from the main developed part of a metropolitan area (Tsai, 2005). Typically a more sprawled landscape experiences decreasing continuity of built-up land. We adopted and used the definition and the model from the Urban Landscape Analysis Tool (ULAT) developed by Parent et al (2009). New development is any built-up land added between two time periods (T1 and T2). The classification of new development in T2 is based on location relative to the urban footprint in T1 (Figure 2). The urban footprint in T1 is defined as impervious surfaces and any open space likely to impact the city. The classification of new development is divided into infilling, edge-expansion or spontaneous growth. Infilling development is defined as “newly developed pixels that are in the urbanized area of the previous time period.” Extension development is defined as “newly developed pixels that are in the fringe area of the previous time period.” And leapfrog development is defined as “newly developed pixels that are outside of the rural area of the previous time period.” Any built-up areas in T2 where there is no contiguity with the previous developed areas (T1) are considered to be leapfrog development areas. Smaller infilling percentage values indicate a greater degree of sprawl.

Scattering: this is a measure for characterizing how developed land parcels are isolated from each other. Concentration is the extent to which development is confined to a relatively small portion of a jurisdictions’ total land area. A wide variety of techniques are employed in measuring concentration including, Shannon’s entropy (Yeh and Li, 2001) and the global Moran‘s I coefficient (Tsai, 2004). Some techniques are based on distance measures. Examples include the Euclidean nearest neighbor (ENN) distance, proximity (PLADJ) and Clumpy. These are landscape fragmentation measures available by open source GIS software, such as FRAGSTATS. For this study, we used mean Euclidean nearest-neighbor 

distance (ENN_MN) to measure the degree of scattering. Euclidean nearest neighbor distance (ENN) has been used extensively to quantify patch isolation and is defined as the shortest straight-line distance between urban patches (McGarigal et al, 2002). Larger ENN values indicate a greater degree of sprawl. 

Shape/Fractal dimension: shape complexity is another important attribute of sprawl. Since we are interested in compactness, shape indicators can be used to describe compact shapes with low values. Fragstats (McGarigal and Marks, 1995) provides diverse measures based on perimeter-area relationships. The simplest shape index is a straightforward perimeter-area ratio (PARA). This shape index (SHAPE) measures the complexity of patch shape compared to a standard shape (square or almost square) of the same size, and therefore alleviates the size dependency problem of PARA. Another other basic type of shape index based on perimeter-area relationships is the fractal dimension index. Perimeter-area fractal dimension (PAFRAC) is appealing because it reflects shape complexity across a range of spatial scales (patch sizes). Larger PAFRAC values indicate a greater degree of sprawl. For example, small and large patches alike have simple geometric shapes, then PAFRAC will be relatively low, indicating that patch perimeter increases relatively slowly as patch area increases.


The nexus between architecture and landscape – the interstitial space – is a fascinating place for a designer. It is the very edges of things; in nature, in objects and in buildings that are always the most interesting places to me. In the natural environment, it is that fuzzy boundary where the ocean meets the sand, the estuaries where freshwater meets saltwater or where the open forest turns to open grassland. In nature, edges are typically the most rich and fertile areas as resources are available from two different environments.


With this in mind, what I’d like to focus on is the interstitial both at the edges of buildings and site as well as the spaces immediately adjacent. Sometimes there’s a clear visual and physical delineation between the building and the related external space, in other projects they tend to overlap and combine, however most commonly we find they tend to inform each other.

Many years ago in a volume of the magazine Places – by the way, the archive is available to download – there was a great definition of these three approaches, or ‘modes’ as the author (Reuben Rainey) called them, in the relationship of architecture and landscape that captures a way of considering the interstitial space.

These modes are: ContrastMerger and Reciprocity.

I’ll just briefly explain them and then you may want to consider these modes while viewing the selected buildings below. The first mode, Contrast, is fairly obvious and is considered where architecture is juxtaposed with the natural or cultural landscape. Acting as a counterpoint, the building exerts an visual and physical influence of the immediate context through a combination of scale, profile, colour and finishes. There is no transition into landscape at all so that the intrinsic qualities of each are accentuated via Contrast.

The next mode, Merger, is the polar opposite and is where architecture blends or appears integrated with the natural or cultural landscape. Reuben notes that in this mode the building form may reflect the surround topography or even be placed underground to entirely merge with the landscape.

Reciprocity is the third mode and most commonly found. Architecture influences, modifies and shapes the landscape and landscape influences, modifies and shapes the architecture. Each mutually benefits which tend to lead to richer, more complex buildings and spaces. The Reciprocity strategy may be as direct and formal as an extension of the building grid into the landscape or more subtle where the external space transitions into the building and interlocks the interior and exterior.

Of course, in the complexities of design there are contradictions. These three approaches often appear together in one building to accentuate each element in response to formal considerations or perhaps react to functional or climatic conditions. From the examples illustrated above, it could be argued that Fallingwater simultaneously merges and contrasts with the site context. Nevertheless, these modes are readily identifiable if you pause and look closely.


1. Introduction

This reflexion comes from a look over the city, particularly the relationship between the built and the open spaces that constitute it. In this look we came across the enormous importance that the system of open spaces has and has always had on the construction of the city, its balance, its identity and its experience. On a closer approach to the system of open spaces of the city, we were confronted with the existence of typologically qualified spaces and of spaces without any typological attribution but that are, by no means, less important than the former. Open spaces, interstices between the built fabric of the contemporary city, that present a certain continuity and that allow the flow of air, of water and matter, simultaneously with the flow of residents or casual users. Sometimes, besides that flow, an informal appropriation of these spaces as spaces for fun, games and socializing is verified, emphasizing the enormous potential presented in the structure and cohesion of the city as support of the urban experience, of social interaction and, of the development of the sense of community. About these spaces, several questions have been raised concerning its quality and diversity, namely its lack of integration in a recognized urban typology and all the consequences that this determines. However, we considered that this fact, on its own, does not constitute a negative factor, but a distinct reality determined by the ever-accelerating rhythm of the technological, economical, social, cultural and demographic chances.

The need to understand the presence of these spaces leads us to a study and analysis of the evolution of the city and of the transformation process that has been occurring, not only in the conceptual and ideological point of view, but also in morphological terms determined by different social-economical and cultural contexts.

During this project we verified that the characteristic discontinuity of the suburbs was the result of an urban model that, since the 60’s of the 20th century, has given birth to a new concept of city and, in a disorderly growing process, allowed a landscape of problematic suburbs to arise, anarchically, in an unqualified territory. The interstices over which we lean are the consequence of this extensive growth of cities and its suburbs.

Aware of the existence of these unnamed intervals, in the city, the open space continues, frequently, to be called green and to, still, play a secondary role on the construction of the urban landscape. Despite its high potential in the structure and cohesion of the city, these spaces – the interstices and the greens – and the attitude of indifference that has been verified towards its qualitative definition tends to reduce them to nothing more than another index in the city’s statistics.

Thus, it is necessary a new understanding on the urban condition of the interstitial spaces and on the importance of the quality of the landscape. We consider fundamental to implement an intentional and adequate use of these spaces, as a vital condition to its defense, in a positive way, guaranteed by its comprehension and enjoyment, recognizing them as the true potential to the development and experience of the city. They should, then, be acknowledged as spaces of urban cohesion, fundamental and complementary to the built space and its articulation with the surrounding, ecologically, aesthetically, culturally, socially, economically and technologically.

With the purpose of obtaining a bigger understanding on the quality of the landscape, and based on the idea that this should appear as a fundamental structure and a cornerstone on the qualification of the city, we leaned on its inherent multifunctionality.

From here starts the conscious notion that the landscape is a recent conquest in the western culture, being considered as such from the moment Man inscribes it in a determined culture and epoch. Intrinsic to the concept of landscape come the concept of multifunctionality to which the concepts and the practices of production, leisure and protection have always been associated. However, this dimension and multifunctional look are lost with the modern movement where, the sectoral zoning does not allow the coexistence of several roles thus appearing the vague concept of green space, that stretches throughout the entire city homogeneously, amorphous and residually.


Interstitial Urban Regeneration

 CONCLUSION

 An interstitial, cybernetic, polycentric urban strategy, which provides a set of conditions,

rather than define particular urban locations, can create a galaxy of public spaces, a nonhierarchical

pattern of randomly distributed nodal points, so ubiquitous that each unit would

be both special and ordinary. In order to make optimal use of the existing, the stars of the

galaxy can be created in available spaces: the interstices of the urban fabric. Since such a

pattern, emerging from the cracks and interstices of the city, is superimposed on the

existing urban network, it doesn’t need its own connections.

In order to create urban settings for restoration, the interstices - removed from the flow of

traffic and benefiting from the shelter of buildings - need to be transformed into public

gardens: small-scale architectonic interventions where the interaction between city and

underlying landscape is intensified. In an interstitial garden an internal horizon replaces the

landscape horizon and an image of nature provides a narrative reference to the landscape.

To contribute effectively to urban life, interstitial gardens must be part of daily life, and easy

to reach. Since their use is so highly localized, the addition of other gardens will not

saturate demand. They will increase it.


Interstitial

Any analysis of urban development will certainly show that the city has undergone numerous transformations, not only from conceptual and ideological perspectives hut also in morphologic terms determined by different cultural and social contexts. This does not constitute in itself a negative factor; it is simply a distinct reality, determined by the rhythms of technological, economic, social and demographic changes. The extensive growth of urbanisation has raised new questions about the diversity of the urban interstitial void spaces, mainly because of their apparent inability to appropriate a recognisable typology or their lack of an attributed name. In the last decades, the open space, usually called ‘green’ space, has played a subordinate role in the construction of the urban space. The indifference to its qualitative definition tends to reduce these spaces to just another index. Together with high and persistent deficits of environmental infrastructures, there came new attempts to understand the urban condition of the interstitial void spaces and the value of landscape quality. All things considered, it is imperative to proceed to an appropriate and intentional reconstruction of these spaces as a vital condition for its defence, which can be guaranteed by understanding and utilising it.


Interstitial Green Space

We find it necessary to question what contribution local environmental impacts have on the regional scale. In other words, how do you determine if there is value in small-scale, interstitial greenspace redevelopment projects in dense, urban areas? Who stands to benefit? With limited space for greenspace development in cities, the environmental and social impacts of small-scale greenspace merit a more in-depth analysis, especially if the cumulative effects of localized greenspaces may be significant to policymakers on a regional scale. Although direct ecological impacts may vary, the aesthetic and social value of nature interspersed in urban areas can reverberate throughout the entire local community. Future planners and community residents will need to reconsider what greenspace can look like in compact cities and begin to integrate more of the natural environment back into the built environment.


SocioCultural Benefits of Green Spaces

Ecosystem services associated with livability and aesthetics have also been studied in depth, but because they are not easily quantifiable and are highly dependent on stakeholder interests, these services are usually discussed in economic or qualitative terms. The availability of natural open space has been shown to promote social interaction and increase sense of community (Kim & Kaplan, 2004). Stewart et al. (2004) found that the presence of public or semi-public outdoor gathering places promotes community identity. This study also found that by designing the space in a manner that connects people with each other and to places of interest in their local landscape, the desirable end-state of planning is more complete and opportunities for community building are increased.

Urban planners increasingly recognize how spending time in urban green spaces has the potential to reduce stress, alleviate headaches, and increase an overall sense of balance (Hansmann et al., 2007). Open space encourages exercise, which increases health and lowers the risk of disease, as well as alleviating anxiety and depression (Sherer, 2003). A review of 16 years of Landscape and Urban Planning (LUP) contributions analyzed studies addressing the issue of contact with nature in urban settings and various ways that contact with nature contributes to improved quality of life, ―even if the encounter is only a brief opportunity‖(Matsuoka & Kaplan, 2008 p.9). These studies illustrate the consistent message that urban residents greatly value nearby natural environments in their community (Matsuoka & Kaplan, 2008). A study by Schell (1999) suggests that urban planners, landscape architects, and citizen groups should recognize these desires as they attempt to mitigate the loss of natural landscape due to growing urbanization and sprawl.


PROXY and PROXY VARIABLES

A Proxy is a measured variable to infer the value of a variable of interest.

In quantitative research, a proxy is a non directly measurable variable.

Although a Proxy variable is not a direct measure of the desired quantity, a good proxy variable is strongly related to the unobserved variable of interest.  

When you cant DIRECTLY measure something, so u look at other relationships …

For instance, the width of a tree ring is a proxy for rainfall and temperature for that year.