iccsa2008cutinibreve

Valerio [email protected]

The periphery as a spatial The periphery as a spatial patternpattern

Working on the edge Working on the edge of townof town

The International Conference on Computational Science and its Applications

Università di Pisa - Dipartimento di Ingegneria Civile________________________________________________________L.I.S.T.A. – Laboratorio di Ingegneria dei Sistemi Territoriali e AmbientaliL.I.S.T.A. – Laboratorio di Ingegneria dei Sistemi Territoriali e Ambientali

ICCSA 2008 – Perugia, June 30th- July 3rd

XXV Conferenza Nazionale A.I.S.Re. - Novara, 6-8 ottobre 2004

In the common sense, the notion of periphery generally refers to several different meanings

marginalization

physical distance

landscape uniformity

functional weakness

poor land values

few public facilities

economic depression

segregation

physical distance

criminality

The notion of The notion of peripheryperiphery

References like that appear to share nothing but a negative meaning

The periphery as an urban disease

The periphery as a problem


Here, the notion of periphery will be approached in a configurational mode

A configurational approach to A configurational approach to peripheryperiphery

Such a view, though partial and not exhausting, allows a better comprehension of several questions

The periphery as a spatial process, depending on the configuration of the urban grid

How do urban areas get peripheral

How can we do to redevelop such areas

Which urban areas can be said peripheral

Which spatial pattern characterises such areas


The thesis we aim at verifying is that

The The thesisthesis of this research. 1 of this research. 1

Not only the position of an urban area with reference to the located activities,

spacedoes matter

but also its spatial pattern with reference to the whole urban grid

and even its intrinsic spatial features

actually influence the way the space itself is used, and concur in determining its level of marginality


The base of configurational theory

Configurational analysis could hardly be considered as a general urban theory

We’d better regard it as a complex of techniques based

on two different points of view over urban phenomena

The assumption of the urban grid as the primary factor

in the formation of movement

in the location of activities

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The interest towards the urban grid with regard to its configuration


It’s the structure of the paths of an urban settlement what dictates the distribution of traffic flows and then, as a consequence, the preconditions for the activities location

The urban grid, hence, implicitly contains the vocation of each area to house activities, according to the benefit they derive from the presence of traffic

The base of configurational theory.The urban grid

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The urban grid merely provides the spatial impedance between couples of activities

Configurational vs interactional logic

Configuration of the urban grid

Distribution of movement and activities

input output

The urban grid is the primary element in movement production and in activities location

Consistency and position of the located

activities

Flows distribution and intensity of mutual

interactions

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To analyse the configuration of an urban grid means to define the characteristics of each of its spaces as resulting from the

relations connecting it to all the other parts of the grid

In a configurational approach, each space in a settlement is appraised on the base of its connections to all the others

Down to the facts, it means to define, for each single element of the system, a set of numeric values correspondent to its configurational indices

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The base of configurational theory.The configuration

The relation between any two spaces depends on their relations to all the other spaces in the system


The solution of the configurational problem

The solution of the configurational problem follows the following logic

The model is processed

The configurational indices, output of the model, are determined

The urban grid is reduced into a system

axial map

visibility graph

Axial analysis

V.G.A.

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The axial analysis

In axial analysis the system to analyse is the axial map

A complex of lines (the longest and fewest ones) that connect all the convex spaces of the grid

The most significant configurational parameter, that we recognise capable to reproduce the distribution of natural

movement (and hence the attractiveness towards activities), is the integration value

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The mean depth of a line from all the other lines of the axial map


The solution of the configurational problem. An example : Siena

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From the urban grid ... to the axial mapto the distribution of integration value

Siena


A different configurational technique: the VGA

As a matter of fact, the operational Space Syntax techniques show some limits

some subjectivity in the construction of the system

the invariability of each configurational index all along the line

Since the late ’90s a different configurational technique has gone arising, so as to overcome such limits: the Visibility

Graph Analysis

the insensitivity towards the role of the open spaces

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On the basis of the same configurational approach, the VGA is characterised by the way the system to analyse is actually constructed

In Space Syntax, the system is assumed as a set of intersected elements (lines), which connect the convex spaces of the grid

In VGA, the system is constructed as a mesh of points (vertices) in mutual visual connection

The only discretionary element in the construction of the system is the density of the vertices, that’s to say the detail

level we expect on the results

The VGA: featuresvalerio cutini


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The configurational techniques.A small example: Palmanova

From the urban layout… … to the urban grid


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An example:the linear analysis of Palmanova. 1

From the urban grid … … to the axial map


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An example:the axial analysis of Palmanova. 2

From the axial map … to the distribution of integration value


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An example:the VGA of Palmanova. 1

to the distribution of integration valueFrom the visibility graph…


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An example:the VGA of Palmanova. 2

to the distribution of clustering coefficientFrom the visibility graph… to the distribution of neighborhood size

K < 1.01.0 < K < 2.02.0 < K < 3.53.5 < K < 5.0

5.0 < K

to the distribution of interaction value


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Some previous results. The correspondence integration vs activities

SienaThe results show an excellent

exponential correlation between the density of the located activities (resulting

from direct observation) and the integration value, resulting

from the processing of the map

Volterra

Such results prove configurational analysis capable to reproduce, by means of the

integration value, the distribution of the levels of

attractiveness within a settlement


The thesis is that an edge urban area, commonly recognised as peripheral, is actually characterised by a specific

spatial pattern

The The thesisthesis of the research. 2 of the research. 2

Those features, setting aside any social, historic, economic functional and architectural aspect, allow to recognise such

areas as peripheral

Configurational analysis, as based on merely spatial elements, allows an easy identification of those

elements

Moreover, on such basis we can identify the possible ways

of removing the spatial factors of marginalization, so

as to mitigate them


As our case studies, we’ve here selected the urban settlements of Pisa and Leghorn, with reference to their edge areas

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Our case studies

More in detail, we’ve analysed the social housing areas, focusing with specific attention on those commonly

recognised as suffering from segregation and urban disease


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The first case study: Pisa and its social housing settlements

1925-1940 1950-1965 1965-1980 1980-1995

“I Passi”

“Gagno”

“CEP”


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The axial analysisof Pisa. 1

to its axial mapFrom the urban grid of Pisa…


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The axial analysisof Pisa. 2

to the distribution of integration valueFrom the axial map of Pisa…


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Pisa: the selected areas and their configurational pattern

“CEP”social housing area

Axial map of Pisa Distribution of global integration value Distribution of local integration value

“I Passi”social housing area“Gagno”

social housing area


Pisa: the selected areas and theirlocal configurational pattern. 1

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“CEP”social housing area Axial map of Pisa

“I Passi”social housing area

“Gagno”social housing area

Distribution of integration value


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Pisa: the selected areas and theirlocal configurational pattern. 2

K < 1.01.0 < K < 2.02.0 < K < 3.53.5 < K < 5.0

5.0 < K

“Gagno”

Distribution of interaction value K

“I Passi”“CEP”


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The second case studies: LeghornThe axial analysis. 1

to its axial mapFrom the urban grid of Leghorn…


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The axial analysis of Leghorn. 2

to the distribution of integration valueFrom the axial map of Leghorn…


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Leghorn: the “Corea” area. Global and local configurational pattern

Distribution of global integration valueAxial map of Livorno

“Corea”social housing area


Distribution of local integration value


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Leghorn: the “Corea” and “La Rosa” areas. Local configurational pattern. 1

Distribution of integration valueAxial map of Livorno


“La Rosa”social housing area


Leghorn: the “Corea” area. Local configurational pattern

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Distribution of interaction valueAxial map of Livorno


K < 1.01.0 < K < 2.02.0 < K < 3.53.5 < K < 5.0

5.0 < K


Leghorn: the “La Rosa” area. Local configurational pattern

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Distribution of interaction valueAxial map of Livorno

“La Rosa”social housing area

K < 1.01.0 < K < 2.02.0 < K < 3.53.5 < K < 5.0

5.0 < K


The The configurational patternconfigurational pattern of the edge areas of the edge areas

On the basis of the results so far, the analysed edge areas appear to share some configurational features

Poor mean values of global integration

The lack of strong local integrators

A weak hierarchy in the distribution of local integration (sameness of IR3 values)

The lack of strong interaction spaces (poor K values)

on a global on a global scalescale

on a local on a local scalescale


ConclusionsConclusions

Such results give use a hint for possible lines we can guess, while discussing redevelopment plans on urban edge

areas

To increase their mean global integration

To set up some strong local integrators

To modulate the distribution of local integration so as to establish a marked hierarchy

To set up some prominent interaction spaces

on a global on a global scalescale

on a local on a local scalescale


Thank youThank you

[email protected]@ing.unipi.it

iccsa2008cutinibreve

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