Abstract

Impacts from vegetation cover and soil sealing stand out in the urban expansion process, since these factors represent elements indicative of urban environmental quality. Unorganized growth in cities that keep their dynamism and attractiveness due to accelerated population growth associated with more soil occupation can be an issue. Teresina City, which is the capital of Piauí State, faces difficulties just as any other Brazilian city; it stands out for growing and spread urban expansion. The aim of the present article is to analyze urban expansion and soil coverage changes in Teresina City, Piauí State, Brazil, by taking into account the years of 2000, 2010 and 2015. Landsat satellite images were interpreted to assess urban soil coverage. The Digital Image Processing (DIP) procedure used the SPRING software (5.1.8) - System for Processing Georeferenced Information - by the National Institute for Space Research (INPE). Software ArcGIS (10.3) was adopted to generate thematic maps. Teresina City presented an accelerated urban expansion process, without balance between soil sealing and vegetated soils. The sealing of large urban soil areas in Teresina, in addition to great vegetal cover losses and to unequal distribution population and basic services distribution, have pointed out that the urbanization process has not been sustainable.

Keywords:
Urban Expansion; Satellite Images; Permeable and Impermeable Soils