Estimativa do índice de vegetação - 2013/2014 - da bacia hidrográfica do Rio Ocoy - oeste do Paraná

Abstract

The watershed of the Ocoy River is an area that possesses human activity interference, for that reason it requires monitoring of the remaining vegetation. First, the objective of this study is to obtain the Normalized Difference Vegetation Index (NDVI) of the dossal of the vegetation in this basin, through Landsat-8 satellite images, with space resolution of 30 meters and radiometric of 16 bits, geo referenced and made available for download by NASA. NDVI was applied on scenes of July 24th, 2013 and February 04th, 2014, in the software Spring of INPE, with values of earnings 200 and offset 50 and Earnings 650 with offset 0, for each image. In this procedure the image of February with earnings 650 and offset 0, was shown with more accentuated contrast than the one of July, considering the same input parameters. In the application of the Earnings 200 and offset 50, the image of July presented better contrast than the one of February. In the thematic mapping on the image NDVI with earnings 650 and offset 0, of February, it was noticed that the segmentation and classification with threshold of similarity 5 and pixel area 30, represented the vegetation with larger details (428 km²) and the exposed soil, on the other hand, the image of July, presented a larger number of thematic classes, in which the vegetation is represented in 314 km² of the basin. The factors of Earnings 200 and offset 50 did not display efficiency in the calculation of the vegetation index. Starting from the digital processing of images, this study made possible the identification of the remainings of the vegetation and of the characteristics of the watershed of the river Ocoy, providing the diffusion of the applicability of this technique to vegetation studies.