Resumo

GOMEZ RODRIGUEZ, Gabriela. Patrones de cambio en la zona de la presa Marte R. Gómez, Tamaulipas, México. Invest. Geog [online]. 1998, n.35, pp.121-134. ISSN 2448-7279.

One of the advantages of land cover monitoring by means of satellite images is to have several observations of a specific place. That gives us the possibility of detecting land changes. This paper exemplifies the use of change detection techniques and illustrates how the combination of digital image information and ancillary data in a geographic information system can give us a much clear idea of the ecological importance of transformations. A semiarid zone, in the Tamaulipas and Nuevo León States was selected. This area, south of the US border, is part of the San Juan River basin. The change image was obtained from the vegetation index difference of 3 Landsat MSS images. This change image was combined with digital land use maps to produce the change distribution. This procedure flags a marked decrease in the extent of the water bodies, an increase in vegetation cover in areas of temporal agriculture and grassland, and the little variation of the forested areas. With the aid of the elevation model it was possible to discriminate the change in areas of high water erosion risk. The loss of the vegetation cover in areas of high slope is not frequent.

Palavras-chave : detecting changes; vegetation index; digital image; geographic information system.

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