3 research outputs found
Avaliação da cobertura vegetal por meio dos Índices de Vegetação SR, NDVI, SAVI e EVI na bacia do rio Japaratuba-Mirim em Sergipe
One of the most important applications of the remote sensing is the use of spectral data to estimate parameters of vegetation. The environmental assessment of river basins has used remote sensing data to obtain information on vegetation cover. The vegetation indices are applied to quantify the areas, types and densities of vegetation cover. This study sought to evaluate the behavior of vegetation in the river basin Japaratuba-Mirim in the state of Sergipe, Brazil, calculating the following vegetation indices: SR, NDVI, SAVI and EVI. We used a Landsat 5 TM (Thematic Mapper), orbit 215, point 67, with low cloud cover, dated 03/04/2009. It was performed atmospheric correction, the conversion of digital number values for reflectance and map algebra to calculate the indices using the software ArcGIS. The results showed that the indices SAVI and EVI were more suitable for the quantification of vegetation, considering the classes of vegetation existing in basin and the limits of literature. SR index showed large coefficient of variation - calculated from the values of image pixels - in comparison to others obtained indices. NDVI index had a poor performance to identification of bare soil and soil with sparse vegetation. However, it was observed that all the indices used allowed a clear distinction between the present vegetation cover.Pages: 1357-136