Análise preliminar das áreas em situação de vulnerabilidade socioambiental de São Sebastião (Litoral Norte, SP)
Tathiane Mayumi Anazawa (tathiane@dpi.inpe.br)
Ana Elisa Pereira da Silva (anaelisa@dsr.inpe.br)
Leila Maria Garcia Fonseca (leila@dpi.inpe.br)
Antônio Miguel V. Monteiro (miguel@dpi.inpe.br)
Flávia F. Feitosa (flavia@dpi.inpe.br)
Abstract
The population issue and the pattern of physical expansion of urban occupations are important factors that shape the urban growth. This paper aims to separate the population of São Sebastião (Northern Coast, SP) in settlement patterns defined by the urbanized area, obtained from satellite images. A LANDSAT 7 multispectral image (ETM+ - 30 m) and a CBERS 2B panchromatic image (HRC - 2.5 m) were fused using the IHS technique for integrating a high spatial resolution panchromatic band with the spectral resolution of other bands with low spatial resolution. After the merger, the image was classified by the Bhattacharya classifier and then corrected by manual edition in software Spring 5.1, in order to delineate the urban areas. The variable population density was quantified, emphasizing its importance to determine a trend in the occupation pattern of occupation of the cities. However, the calculated density is estimated for the area of census tract, in other words, non-urbanized and urbanized areas, which may lead to a distortion of the phenomenon. To minimize this distortion, we chose to work with the boundaries of the urbanized areas of São Sebastião, seeking to observe the population density that best portrays the city. Remote sensing data translated in urbanized areas describe the spatial heterogeneity and enable the most appropriate redistribution of population density. It was observed that area 1 was considered more compact, while the second area show evidences of urban sprawling.
