A Comparative Study of Using Pixel Value, Radiance, and Reflectance for the Vegetation Indices Calculation: A Landsat 8 Case Study

Satellite based vegetation indices have a major rule in the study of earth vegetation cover. These indices could be computed using different quantities, including digital number, radiance or reflectance of the pixels. Study of quantities which the vegetation index based on is calculated could help the simplifying the earth vegetation assessment. In this research 10 vegetation indices are generated using 3 image quantities (digital number, radiance and top of atmosphere reflectance) of a LANDSAT 8 OLI multispectral image. The vegetation indices are: NDVI, EVI, SAVI, RVI, GVI, PD43, VARI, GRVI, NDWI, DVI. The vegetation indices also were generated for soil, water, urban, and vegetation land cover separately as well as for the entire image. The correlation coefficient of the calculated indices have been computed. The results show a strong linear regression among the vegetation indices have been calculated from the three different quantities. A maximum correlation coefficient one have been reached for the most indices. The class of water showed the minimum correlation coefficient 0.8696 for the NDWI. The results show there is no significant difference between the indices calculated from different three quantities when there is no need to the original values of the vegetation indices.