Buildings shade as cities verticalization index

Abstract

This research aimed to correlate the verticalization of Lisbon/Portugal with the presence of shadows from high buildings or narrow streets, by means of a supervised classification within a high-resolution satellite image (0.5-m panchromatic and 2-m multispectral). The obtained results proved to be useful for this purpose, showing the hat effect, with a lot of buildings in a central part and a decreasing of vertical features to the periphery. From an image of June 29th 2010 (Summer in the Northern Hemisphere), from 11:46 a.m., the value found in Lisbon, was 1.3% of shadowing in the urban area, with the central city parish of Misericórdia, with more projected shadows of buildings (7.8%), while the Belém neighborhood, in the opposite, with only 0.5%. Therefore, we can consider the presence of shadows as a good indicator of verticalization, being a very important indicator for the urban planning, who needs to ensure the solar access, ventilation and comfort for all inhabitants.