Refining cartographic representation in São Paulo peri-urban interface

• Grant number: 13/17617-0
• Support Opportunities: Scholarships abroad - Research
• Start date: December 02, 2013
• End date: February 01, 2014
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Ligia Vizeu Barrozo
• Grantee: Ligia Vizeu Barrozo
• Host Investigator: Christopher Sennen Small
• Host Institution: Faculdade de Filosofia, Letras e Ciências Humanas (FFLCH). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Columbia University in the City of New York, United States

Abstract

Brazilian Census occurs each ten years when the geometry of census blocks and census survey areas are remodeled according to the population growth. In 2010 Census, São Paulo presented 18,363 census blocks and 310 weighting census survey areas. Despite the fullness of census data, the cartographic representation presents important constraints regarding to population distribution. The geometry of census blocks does not exclude important uninhabited areas in the city as parks, cemeteries, airports, reservoirs and vegetation. This is most striking in the peri-urban interface where the land use is mixed and the census blocks have small population, occupying large areas and giving the notion that population is homogeneously distributed. Hence, when socio-demographic indicators are mapped based on the total area of the administrative unit using the choropleth mapping technique, the cartographic representation leads to a distorted notion for urban planning purposes. When the primary data and social indicators are focused on public health planning, the distortion is still worse, because the general premise wrongly assumes that the population is uniformly distributed over the area. To address this misrepresentation we applied dasymetric concepts based on the polygons of the city blocks linked to the aggregated municipal fiscal cadastre. Then, we linked this detailed base map to the census blocks and weighting census survey areas identifiers, allowing mapping any census variable and health indicators on it. Nevertheless, the peri-urban interface is still represented by large polygons even when they are uninhabited because ancillary data used in this first approach did not contain detailed location of built-up areas in the rural census blocks.Over the last ten years population increased 6.4%. In the urban area, population growth corresponded to ~12%, while rural population decreased 83.7%. This occurred due to land use changes and census block classification that were altered from rural to urban. This rapid change occurred mainly in the peri-urban interface with important shifts in the landscape. To better depict population distribution it is necessary to map the built-up areas and edit the official polygons of rural census blocks proposed by 2010 CensusThus, the purpose of this research is to explore the use of ancillary spatial data, particularly from remote sensing, for refining the spatial structure of polygonal units in the peri-urban interface of São Paulo. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

BARROZO, LIGIA VIZEU; PEREZ-MACHADO, REINALDO PAUL; SMALL, CHRISTOPHER; CABRAL-MIRANDA, WILLIAM. Changing spatial perception: dasymetric mapping to improve analysis of health outcomes in a megacity. Journal of Maps, v. 12, n. 5, p. 1242-1247, 2016. (10/12619-7, 13/17617-0)