Urban mapping and impacts assessment in a Brazilian irregular settlement using UAV-based imaging

Abstract

Remote sensing methods has been commonly used by urban planners for irregular settlement management, however, they can be expensive considering the financial resources context of some cities. In Brazil, from the legal and planning perspective, irregular urban occupations need to be regularized to become an effective part of the city. In order to initialize the regularization process, Brazilian legislation requires a complete georeferenced planialtimetric survey, mapping constructions, properties boundaries, existing urban infrastructure and environment features (for impacts assessment). Given this context, we conducted an assessment to the potentialities of using Unmanned Aerial Vehicle (UAV) products to map a favela located in the Brazilian city São José do Rio Preto (São Paulo State). From UAV image acquisition, an orthomosaic (3.2 cm2/pixel), a digital surface model (DSM), a digital terrain model (DTM) and topographic contours were built. These products were used to provide the essentials requirements for subsidizing urban land regularization, being promising for environmental and social impacts identification such as deforestation, soil erosion, irregular waste and sewage disposal and lack of basic infrastructure. The use of UAV proved to be an efficient and low-cost alternative compared to the conventional aerial survey and commercial high-resolution satellite images.