Using satellite remote sensing for DEM extraction in complex mountainous terrain: landscape analysis of the Makalu Barun National Park of eastern Nepal

The design and management of national parks and other protected areas requi res a broad base of physiographic and geo-ecological information about the landscape. This paper evaluates the effectiveness of satellite remote sensi ng for photogrammetric stereo-mapping and digital elevation model ( DEM) ex traction within remote mountainous terrain. As a case study, a landscape an alysis of the Makalu Barun National Park and Conservation Area of east Nepa l ( 27.5 degrees N, 87.0 degrees E) was examined. The study area is a highl y complex and rugged mountain landscape, with extreme topographic relief an d an elevation gradient spanning more than 8300 m. A DEM extracted from ste reo SPOT imagery resulted in a median disagreement of 58 m when compared to a DEM generated from a conventionally digitized GIS dataset of topographic contours (scale= 1:250000). Visual comparison of the two DEMs showed subst antial agreement at the landscape scale, while larger scale comparison of 1 00 m contours revealed some localized differences. The SPOT extracted DEM p rovided equal or better basis for orthorectification of satellite imagery w hen compared to the conventional DEM. Derivative landscape analysis outputs , such as hydrological modelling, drainage networks and watershed boundarie s, compared well with results based upon the conventional dataset. Intermed iate map products useful for field research and mapping included production of an orthorectified satellite base-map image. Additionally, a fused multi sensor high resolution image of the study area, combining Landsat Thematic Mapper ( TM) and SPOT imagery at 10 m resolution, was orthorectified to pro duce a false-colour satellite image map highlighting the spectral discrimin ation between land cover classes.