An assessment-based process for modifying the built fabric of historic centres: the case of Como in Lombardy
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The document outlines the methodologies and processes used in assessing the suitability for change of historic centers, focusing on urban modeling, spatial statistics, and the socioeconomic vitality of built fabrics. It discusses various indices and algorithms developed to evaluate urban centers, including the evaluation of centrality, commercial distribution, and the characteristics of the built environment. The goal is to create a comprehensive map showing the types of changes suitable for specific buildings based on a multidimensional analysis of demographic and economic factors.
![Sixth International Workshop on "Geographical Analysis, Urban Modeling, Spatial Statistics" GEOG-AN-MOD 11 in conjunction with The 2011 International Conference on Computational Science and its Applications (ICCSA 2011) June 20 th to June 23 th, 2011, University of Cantabria, Santander, Spain Pier Luigi Paolillo(1), with Alberto Benedetti, Umberto Baresi, Luca Terlizzi, Giorgio Graj (1) Polytechnic of Milan [email_address] - http://webdiap.diap.polimi.it/paolillo/](https://image.slidesharecdn.com/pptpapersantander-110628094851-phpapp02/85/An-assessment-based-process-for-modifying-the-built-fabric-of-historic-centres-the-case-of-Como-in-Lombardy-1-320.jpg)
An assessment-based process for modifying the built fabric of historic centres: the case of Como in Lombardy
- 1. Sixth International Workshop on "Geographical Analysis, Urban Modeling, Spatial Statistics" GEOG-AN-MOD 11 in conjunction with The 2011 International Conference on Computational Science and its Applications (ICCSA 2011) June 20 th to June 23 th, 2011, University of Cantabria, Santander, Spain Pier Luigi Paolillo(1), with Alberto Benedetti, Umberto Baresi, Luca Terlizzi, Giorgio Graj (1) Polytechnic of Milan [email_address] - http://webdiap.diap.polimi.it/paolillo/
- 2. 1. Why the historic centres : a preliminar consideration 2. The methodological process : from the selection of descriptor and variables to the final synthesis in the “ suitability for change” map 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality 4. Assessing the values of the built fabric 5. The final step: the map of suitability for change and the relative types of change for the single built fabrics Use an algorithm to create scenarios of suitability for change 0. The framework assumed Estimate: (α) residenzial vitality (β) commercial distribution (γ) services accessibility ASSUMPTION OF THE BEST SCENARIO FOR SUITABILITY FOR CHANGE OF BUILT FABRICS Results: Socio/economic characterization 5 scenarios derived from “f” function Regional Laws Support to administration Identify types of change in built fabrics (art. 27 Lr.12/05) Classify priority of intervent in historic centre Goal: Define degrees of suitability for change of single buildings Goal: Identify and quantify demographic, economic, social tendency Suitability for change Social and economic phenomena Database organised to develop Gis analysis Multi/dimensional analysis Comparison between scenarios and socio/economic aspects, and selection of the best-one
- 3. Urban Planning Discussion-ANCSA: Growing importance (since 50’s) of “historic centres” issue, related today with a generalised decay: RELATIONAL (population and vacancy) STRUCTURAL (appeal and economy) PHYSICAL (built fabrics) 1. Why the historic centres: a preliminar consideration REGULATION assessment in LOMBARDY: LR.12/2005: NEW PLANNING INSTRUMENT, PGT Goals: identify HISTORIC CENTRES recognize Types of change for each fabric Structuring the method: Necessity of a different approach based on quantitative analysis Preliminar analysis of the case-study: territorial phenomena and planning instruments; Use of the database to develop analysis and evaluations with Gis software Como historic centre : Worsening in terms of : weakness in human relations lost of attractivity Growing decline and vacancy in built fabrics Change of approach : 60’s * conservation of historic fabrics Today * re-use of built fabrics, in order to: - not use further free-soil - use fabric nowadays vacant
- 4. 2. The methodological process : from the selection of descriptor and variables to the final synthesis in the “ suitability for change” map Identifying the variables Grouping the variables into summary indices Socio/ economical aspects Identifying the spatial units of investigation Historic/ architectural aspects Multidimensional/ algorythm analysis Areas of iso-problematicity Scenarios for change Identifying the descriptor blocks Selecting the most suitable scenario for change in this specific place Spatialising the phenomena (thematic mapping)
- 5. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Function indicating how various phenomenical aspects flow together into the socio/economical analysis where: A = tendency to accumulated centrality of the historic centre; B = instability of the fabric due to monofunctionality; C = density of localisation of the most strongly attractive activities; D = stability of the inter-relating residential fabric; E = urban landscape importance of buildings Innovative tools and applications Multiple centrality assessment - Porta et al ., 2006; Cardillo et al ., 2006; Crucitti et al ., 2006; Scellato et al. , 2006 - Similar approach to configurational analysis (Bill Hillier and the UC London school) - Moving from space configuration to recognize structure and caracteristics of open urban spaces Viewshed Viewshed analyses: common function of most Gis software. The analysis uses the elevation value of each cell of the Dem to determine visibility to or from a particular cell Application of viewshed to built fabric with specific carachteristics (constraints, facades, uniformity of a specific built-area)
- 6. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Indices and variables A) Mca (Multiple centrality assessment) Goal: recognize the inclination towards transformation of built fabrics Indices: Betweenness -> traffic long-radius Local closeness -> traffic short-radius Land use density -> concentration of extra-residential buildings Functional heterogeneity -> application of Shannon index to calculate heterogeneity Basis: Connection from point to point to create Axial map (ecuclidean axis) with Mca tools Betweenness (x) Local closeness (y) Network interaction (a1) Land use density (x) Functional heterogeneity (y) Vitality of the economic fabric (a2)
- 7. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Indices and variables B) Instability of the fabric due to monofunctionality Goal: Recognize areas with potential risk of becoming monofuncional and central “banlieue” Indices: Index of ageing -> areas with old inhabitants Residential density -> areas with inhabitants Index of heterogeneity of non-residential activities -> monofuncional areas Basis: Make residential and economical data interacting toghether using Kernel Density Index of ageing Residential density Index of heterogeneity of non-residential activities Thematic activities
- 8. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Indices and variables C) Density of localisation of the most strongly attractive activities Goal: Recognize the competitive areas from the economic point of view Indices: Density of commercial activities Density of service sector activities Density of commercial activities D) Stability of the inter-relating residential fabric Goal: Recognize problematic residential areas Indices: Incidence of the non-Italian resident population Incidence of residential vacancy Distribution of the population within buildings (underoccupation – overcrowding) Density of service sector activities Vacancy Indices Variables Resident nationality Residential buildings size Roots Census of built fabric Residential dataset Census of built fabric
- 9. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Indices and variables E) Urban landscape importance of buildings Goal: Recognize buildings with particular landscape values Indices: Buildin g perception -> is the building seen from relevant points of observation? Characterisation of the perception -> how is the building perception? Basis: Advanced applications in Gis softwares: * building the ( Digital Elevation Model ); * selecting points of observations; * building Viewshed Building DEM (DTM+Built fabrics) Building VIEWSHED Points of observation Fabrics with positive elements Fabrics with negative elements Quantity of fabric percepted Urban landscape importance of buildings
- 10. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Viewshed procedure Decomposing the observation points into a number of different viewshed analyses (e.g.: access points to the historic centre, busiest historic streets, open spaces for public socialising, and so on) Selecting observation points Sifting informational strata Summarising , referring as necessary to the qualitative characterisation of the particular building (E) Quantifying and summarising the degree of visibility of any given building Refining the analysis as appropriate (e.g.: distinguishing between buildings seen in perspective and buildings seen in the round ) Analysis: if k = 1 the building is visible
- 11. 3. Method for analysing and assessing the characteristics of centrality and socioeconomic vitality Applied multidimensional geostatistic analysis correlational analysis , aimed at reducing the number of variables to be tested and used in the subsequent stages; non-hierarchical analysis , which makes it possible to identify the spaces that are homogeneous in terms of the variables adopted for describing the model From variables and indices to Multidimensional analysis Use of dedicated software Addawin (prof. Griguolo, IUAV of Venice) in the GIS environment: from aggregated indicators derived estimating f (A, B, C, D, E), to application of geostatistics procedures, in particular multivariate analysis: Facplan image: step that analyses the distribution of the centres of the stable profiles with respect to the two axes that most effectively explain the multivariate situation under investigation Phenomena Clusters
- 12. 4. Assessing the values of the built fabric Function indicating how various phenomenical aspects flow together into the built fabrics analysis where: F = suitability for retention, intrinsic in the building itself G = suitability for retention, in the relationship between building and urban block H = the urban landscape importance of the context in which the building stands I = suitability for increases in volume Assumption of descriptors block and variables
- 13. Indices and variables F) Suitability for retention, intrinsic in the building Goal: recognize the inclination towards transformation of built fabrics Indices/variables: F1 - presence of environmental and historic/architectural constraints F2 - persistence of buildings over time F3 - the state of conservation of buildings F4 - presence of facades to be retained F5 - presence of excrescences F1 - Contraints F2 - Datation F3 - Conservation F4 - Facades F5 - Excrescences 4. Assessing the values of the built fabric
- 14. Indices and variables G) Suitability for retention, in the relationship between building and urban block Goal: recognize the inclination towards transformation of built fabrics, in the relation with the urban blocks Indices/variables: G1 - presence of transformed areas (causing discontinuities in the urban fabric) G2 - degree of uniformity in respect to the first historic threshold adopted G3 - degree of uniformity in respect to the number of storeys G1 – Transformed areas G3 - Uniformity (number of storeys) G2 – Uniformity (first historic threshold) 4. Assessing the values of the built fabric
- 15. Indices and variables H) Urban landscape importance Goal: recognize the built fabrics impact on perception Indices/variables: H1 – presence of quality elements H2 – presence of elements of contrast H3 – index of perception of the building H4 – incidence of the building on the public space H4 – Perception from public spaces H3 – Index of perception (from historic roads, points of access, public places) H2 – Contrast factors H1 – Quality factors 4. Assessing the values of the built fabric
- 16. Indices and variables I) Suitability for increases in volume Goal: recognize the building that can be raised as number of storeys Indices/variables: I1 – character of the existing built frontage I2 – possibility of adding extra storeys 1 – Built-front with at least 50% fabrics with same height 3 –Buildings useful for raising storeys 4 –Buildings unuseful (as reference) for raising storeys 2 – Buildings with specific characteristics 4. Assessing the values of the built fabric
- 17. Algorhythm for assessing suitability for change 4. Assessing the values of the built fabric Assumption of an algorithm to classify the built fabrics Classification of the result values Aggregation of variables and indices in thematic blocks Assumption of different classes of suitability for change, for every built fabrics of the historic centre
- 18. 4. Assessing the values of the built fabric Building and selecting scenarios of suitability for change Devising the basic algorhythm of suitability for change Creating scenario 1 Types of change permitted by the regulations Correlating the classes of suitability for change to the consented methods of changes to buildings Preparing the map of suitability for change Devising different scenarios Territorial socioeconomic configurations Comparing scenarios and selecting the scenario that is most compatible with these territorial configurations
- 19. 4. Assessing the values of the built fabric Classifying and comparing different scenario outputs internal consistency : correlation between suitability for change and the dataset of variables adopted, identifying excessively high interdependencies that would indicate a flattening of the outcomes of the multivariate analysis ii ) external consistency is the correspondence between the general character of the scenario, in terms of suitability for change , and the real social, economic, and demographic characteristics of the territorial configurations of the historic core Building and selecting scenarios of suitability for change
- 20. 5. The final step: the map of suitability for change and the relative types of change for the single built fabrics Final scenario of suitability for change Cartography From classes to types of change on built fabrics
- 21. 5. The final step: Comparison between prescriptions of the old Prg and the new assessment recognized by Pgt From a homogeneous classification of buildings To a new one, coherent with the specific characterization of the single built fabrics Previous planning instrument: Prg -General regulator plan (1975-1993) New planning instrument: Pgt -Plan for territorial government (2010)
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