Distance-based vegetation indices computed by SAGA GIS: A comparison of the perpendicular and transformed soil adjusted approaches for the LANDSAT TM image

Landsat-TM of 2001 covering Iceland (15.5°W-21°W, 64.5°N-67°N) was processed using SAGA GIS for testing distance-based Vegetation Indices (VIs): four approaches Perpendicular Index (PVI) and two Transformed Soil Adjusted TSAVI. The PVI vegetation from the soil background line indicated healthiness as a leaf area index (LAI). results showed that reflectance has linear relation with line. Four models TSAVI shown coefficients determination LAI. dataset demonstrate variations in calculated coefficients. mode histograms based on different algorithms show difference:-7.1,-8.36, 2.78 7.0. TSAVI: first case ranges 4.4.-80.6 bell-shape histogram (8.09 to 23.29) algorithm an irregular shape second several modes starting 0.11 0.2 decreasing 0.26. permits calculation by computed NDVI intersection background. Masking NIR R, regression grids performed equation embedded GIS. advantages consists adjusted position pixels brightness which refines it comparing slope-based VIs. paper demonstrates application agricultural studies.