id 
caadria2020_384 
authors 
Patt, Trevor Ryan 
year 
2020 
title 
Spectral Clustering for Urban Networks 
source 
D. Holzer, W. Nakapan, A. Globa, I. Koh (eds.), RE: Anthropocene, Design in the Age of Humans  Proceedings of the 25th CAADRIA Conference  Volume 2, Chulalongkorn University, Bangkok, Thailand, 56 August 2020, pp. 91100 
summary 
As planetary urbanization accelerates, the significance of developing better methods for analyzing and making sense of complex urban networks also increases. The complexity and heterogeneity of contemporary urban space poses a challenge to conventional descriptive tools. In recent years, the emergence of urban network analysis and the widespread availability of GIS data has brought network analysis methods into the discussion of urban form. This paper describes a method for computationally identifying clusters within urban and other spatial networks using spectral analysis techniques. While spectral clustering has been employed in some limited urban studies, on large spatialized datasets (particularly in identifying land use from orthoimages), it has not yet been thoroughly studied in relation to the space of the urban network itself. We present the construction of a weighted graph Laplacian matrix representation of the network and the processing of the network by eigen decomposition and subsequent clustering of eigenvalues in 4dspace.In this implementation, the algorithm computes a crosscomparison for different numbers of clusters and recommends the best option based on either the 'elbow method,' or by "eigen gap" criteria. The results of the clustering operation are immediately visualized on the original map and can also be validated numerically according to a selection of cluster metrics. Cohesion and separation values are calculated simultaneously for all nodes. After presenting these, the paper also expands on the 'silhouette' value, which is a composite measure that seems especially suited to urban network clustering.This research is undertaken with the aim of informing the design process and so the visualization of results within the active 3d model is essential. Within the paper, we illustrate the process as applied to formal grids and also historic, vernacular urban fabric; first on small, extract urban fragments and then over an entire city networks to indicate the scalability. 
keywords 
Urban morphology; network analysis; spectral clustering; computation 
series 
CAADRIA 
email 
trpatt@gmail.com 
full text 
file.pdf (4,152,122 bytes) 
references 
Contenttype: text/plain

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last changed 
2020/08/14 18:40 
