Vegetation monitoring has been one of the main targets of remote sensing study. A vegetation-soil-water Index (VSWI) is defined to monitor land cover conditions based on empirical fact that a visible red versus near infrared scattergram of any satellite data generally forms a triangular distribution. Three vertices of the triangular distribution (end member triangle) correspond to end members for vegetation, bare soil and water (or dark target). The VSWI measures the distances from data point to three edges of the end member triangle. For vegetative component, the distance from data point to the opposite side of end member for vegetation, and so on. The VSW index has possibility to monitor not only vegetation conditions but also soil and water conditions as well. In the present study, the VSW index was used to monitor land cover conditions of mountainous region in Japan with LANDSAT TM images. A change in VSWI around MT. Fuji was also examined using two LANDSAT TM scenes.
"Monitoring land cover with a vegetation-soil-water index", Proc. SPIE 3499, Remote Sensing for Agriculture, Ecosystems, and Hydrology, (11 December 1998); doi: 10.1117/12.332750; https://doi.org/10.1117/12.332750