Absolute Accuracy of the Erosion Model of DEM-NDVI and Its Modification

Abstract

The research aims at studying the absolute accuracy of the erosion model of DEM-NDVI and its modification (DEM-MSAVI, DEM-SAVI, DEM-TSAVI, and DEM-TVI). Methods applied were by analysing various vegetation indices (NDVI, MSAVI, SAVI, TSAVI, and TVI) of Landsat 7 ETM+ data, while Digital Elevation Model was analysed using contour line. Erosion rate within the watershed (Emodel) then were calculated. The results of Emodel then were compared to the actual erosion (Eactual). The results show that 3 Emodel (DEM-NDVI, DEM-TSAVI and DEM-TVI) have the high correlation with Eactual (the r-value are ≥ 0.80), while 2 Emodel (DEM-MSAVI and DEM-SAVI) have low correlation, 0.62 and 0.73 respectively. Only Emodel of DEM-TVI, reached the absolute accuracy of ≥ 80% (ie. 95.47%), while the original model (DEM-NDVI) only 55.39%. The result also revealed that modification resulted in the higher absolute accuracy, as from 55.39% to 69.12% (DEM-MSAVI), to 65.88% (DEM-SAVI), to 64.90% (DEM-TSAVI), and to 95.47% (DEM-TVI).