The applicability of VIs from MODIS in estimating vegetation cover in the middle and lower reaches of the Tarim River

To more accurately determine vegetation information for the mid-lower reaches of the Tarim River in an arid desert region, we used MODIS data to calculate commonly used vegetation indices (VIs, normalized difference vegetation index NDVI, difference vegetation index DVI, enhanced vegetation index EVI, ratio vegetation index RVI). We combined remote sensing data using Image J software to acquire a vegetation coverage, and compared them with actual measurements. We concluded that they were significantly correlated. Next, we made a vegetation coverage map via Image J and vegetation indices in a 2D scatter plot using regression analysis. Finally, we chose the most suitable VI among the four VIs. The study showed that each VI was positively correlated with vegetation coverage. The goodness of fit between VIs and vegetation coverage was ranked: NDVI, EVI, RVI, and DVI. Thus, we suggest the use of NDVI as the VI.