Mosaic in g the ocean/terrestrial SRTM-DEM and making t he geomorphologic relief shading map

Abstract

Ocean and terra are the largest geomorphologic units on the earth, and there are essential differences between them. Hence, while we make the geomorphologic relief shading map, it is necessary to make the ocean/terrestrial geomorphologic relief shading map respectively. Then combining the ocean and terra map, we can get a whole geomorphologic map about the study area. However, the SRTM-DEM(Shuttle Radar Topography Mission-Digital Elevation Model) we get from USGS(United States Geological Survey) is clipped by SWBD(Shorelines and Water Bodies Database) coastline, so the coastline may be not accordance with the coastline we get about the study area. To solve this problem, we had to clip the DEM and patch the void data. Only in this way can we assure the DEM is accordance with the coastline. If the DEM is larger than the coastline, we can cut the spare parts by using the tool - extract by mask. However, if the DEM is smaller than the coastline, we have to patch the void data. This paper tries to find the best interpolating method to patch the void area according to the geomorphologic units. After that, we illustrate the processes of how to make the geomorphologic relief shading map by the software - Global Mapper.