Timberline change detection using topographic map and satellite imagery: a critique

摘要

Remote sensing is a valuable tool for geo-spatial bio-resource mapping and monitoring land use / land cover changes. Change detection using remote sensing, especially in the rugged mountains such as higher Himalaya, requires a series of careful steps including selection of appropriate methodology and sufficient ground knowledge. Based on remote sensing techniques a recent study by Panigrahy et al. (2010) reported an upward shift of timberline vegetation by 300 m and a considerable reduction in snow cover in Nanda Devi Biosphere Reserve (NDBR), Garhwal Himalaya. Their study has overlooked a number of methodological issues and misinterpreted some of the vegetation classes. In this communication we provide a brief critique on the methodology adopted by these authors and suggest certain precautions while undertaking change detection studies in the Himalayan region using remote sensing techniques.