DESCRIBING THE VERTICAL STRUCTURE OF INFORMAL SETTLEMENTS ON THE BASIS OF LIDAR DATA – A CASE STUDY FOR <i>FAVELAS</i> (SLUMS) IN SAO PAULO CITY

• Main Authors: S. C. L. Ribeiro, M. Jarzabek-Rychard, J. P. Cintra, H.-G. Maas
• Format: Article
• Language: English
• Published: Copernicus Publications 2019-05-01
• Series: ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
• Online Access: https://www.isprs-ann-photogramm-remote-sens-spatial-inf-sci.net/IV-2-W5/437/2019/isprs-annals-IV-2-W5-437-2019.pdf

Cadastral mapping of <i>favela</i>’s agglomerated buildings in informal settlements at Level of Detail 1 (LoD1) usually requires specific surveys and extensive manual data processing. Therefore, there is a demand for including the <i>favelas</i> in the city map production on the basis of Lidar surveys, as well as the detection of their vertical growth. However, the currently developed algorithms for automatically extracting buildings from airborne Lidar data have mainly been tested only for regular building reconstruction. This study aims to develop a Lidar data processing pipeline enabling to compute metrics related to intraurban informal settlements. To do so, we present a procedure to generate <i>favela</i>’s buildings delineation, height, floors’ number and built area and apply them to six case studies in <i>favela</i> typo-morphologies. We conducted an exploratory analysis in order to obtain the adequate parameters of the processing pipeline and its evaluation, using open source, free license and self-developed software. The results are compared to reference data from the manual stereo plotting, achieving a quality index in the building reconstruction about 70%. We also calculated the growth density, measured by gross Floor Area Ratio index inside settlement, revealing values from 29% to 74% considering different time periods.