The use of satellite images is an important tool to identify natural features and monitor land use and occupation. This tool enables the definition of zonings that may help planning actions focused on environmental preservation and reclamation. Earth images taken from satellites make it possible to obtain products of wide application for studies on agriculture, urban, climate and environmental areas, among others, besides monitoring several phenomena over time.
CEPSRM – Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia (State Center of Researches in Remote Sensing and Meteorology) elaborated a Mosaic of Images of Rio Grande do Sul in scale 1:1,000,000, where 22 images LANDSAT TM 5 and 7 of 185km² were used in all spectral bands, providing full coverage of the state territory with final resolution of 240X240m. The use of images of the same period of the year (summer 1999/2000) allowed a better definition of the vegetation cover, since it expressed data in similar conditions of soil moisture, development stage of vegetation and atmospheric conditions.
The Mosaic of Images has a false color composition, using three spectral bands (3.4 and 5) where the shades closest to green represent woody vegetation related to the presence of remaining forests or forestation (pine, eucalyptus and acacia); the shades closest to yellow/light green represent areas of intensive cultivation of winter and summer (mainly soybean, corn and wheat) or coverage of altitude camps; and the shades closest to orange correspond to vegetation cover with predominance of clean or subshrubby fields with or without interspersed agricultural areas, where rice-growing areas prevail.