P1.14
Urban environmental analysis from high-resolution Digital Elevation Models (DEMs)
Carlo F. Ratti, University of Cambridge, Cambridge, United Kingdom; and P. N. Richens and M. Trinder
In recent years, Digital Elevation Models (DEMs or gridded matrices of elevation values) have become an increasingly common support for environmental modeling. This is due to their elementary data format, which is conducive to a series of simple and fast computer algorithms.
Most of the applications developed to-date tend to use large-scale DEMs, where the size of each pixel is between 10 and 40 meters. The research presented in this poster aims at developing a new range of analysis techniques to work at finer-resolution in urban areas (pixel size approximately 1m, extents of the DEM a few city-blocks). Because of the discontinuous nature of the surface of the city and the particular nature of environmental processes within the urban canopy, the algorithms that we have developed differ substantially from those that are commonly used in the geosciences.
By adapting a number of image processing techniques, we have been able to very quickly derive parameters such as: shadowing for changing sun positions, view-factors from the city to the sky, various visibility parameters at the ground level, measures of the accessibility of streets, mathematical transformations such as the Fast-Fourier and the Radon Transform, indexes of urban porosity, evaluations of energy consumption of the urban fabric, etc.
The poster will use colored images to present results for three case studies in London, Toulouse and Berlin. In addition, it will include some notes on the derivation of the different parameters. The techniques aim to contribute to the understanding of urban microclimate and to help planners and designers to assess the environmental potential of different design options. We claim that they might have a definite impact on urban studies when high-resolution urban databases become available at low cost – a condition that should be met in the coming years due to advances in digital photogrammetry and remote sensing.
Some images to support this abstract are available on the Internet at the URL:
http://www.arct.cam.ac.uk/research/AMS/AMSimages.pdf
Poster Session 1, Urban Posters
Thursday, 17 August 2000, 1:30 PM-3:00 PM
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