The increase of artificial lakes as a result of sand mining activities, in the Paraíba do sul River Valley Basin, São Paulo State, Brazil

Abstract

Object-oriented paradigm is an alternative to the conventional "pixel-to-pixel" image classifiers, since it take into account the topologic and geometric information relating to the objects. The area being studied by this paper corresponds to the part of the Paraíba do Sul River basin located within São Paulo state, on a regional scale, and to the municipality of Tremembé, on a local scale. This region is notable for the large quantities of sand it produces for the construction industry-mostly for the Metropolitan Region of São Paulo. This economic activity has been having a negative impact on the environment in the form of artificial lakes. This study is committed to exploring the object-based image analisys in the mapping of the use and occupancy of the land, with an emphasis on the monitoring of the lakes arising from the sand mining process, using Landsat 5-TM images of the entire basin, corresponding to UGRHI number 2-Paraíba do Sul River Basin-taken over three different decades (1986, 1996 and 2007) and Ikonos-2 images from the municipality of Tremembé. The DEFINIENS (v. 7.5), ENVI (v. 4.6.1) and ArcGis (v. 9.3.1) software programs were used in the pre-processing, segmentation, classification, evaluation of classification, data analysis and layout preparation procedures.