Use of topographic correction in Landsat TM-based forest interpretation in Nepal

Abstract

The land use of two districts in western Nepal was classified into forest and non-forest by satellite imagery with different topographical corrections. The accuracy of the forest biomass and timber volume estimates was also tested. The forest areas were interpretated correctly, with an accuracy of 82-88%. The best result was derived when the Minnaert constants of forest were separated from those of other land uses which were combined. The timber volume and biomass estimates were computed using the weighted nearest neighbour method. The coefficients of determination were 0.06 for timber volume and 0.09 for biomass. The use of the existing land use data seems to have potential for improving the results of topographic normalization. Because the reflectance in mountainous areas depends on many vegetative and terrain features, the simple non-Lambertian correction over broad categories did not significantly improve the results.