Derek Watkins has created a simple and easy to use interface for downloading 30-Meter SRTM data.
Based on measurements from NASA’s Terra spacecraft, a new 3D topographic map has been released as a joint effort by NASA and Japan. The digital elevation model (DEM) was developed from imagery obtained from the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, instrument aboard Terra. ASTER is one of five […]
Launched on June 21st of this year, the first images from TanDEM-X have been acquired and processed 3.5 days post launch. As the name implies, the goal of TanDEM-X (which stands for TerraSAR-X add-on for Digital Elevation Measurement) is to generate a high-accuracy global Digital Elevation Model (DEM). The scientific use of the data can be […]
Hypsography, topography, elevation, TINS, and contours. There are many different terms for data relating to elevation. This article reviews some of terminology and types of elevation based datasets available to GIS. Digital elevation data are sets of elevation measurements for locations distributed over the land surface. Elevation data have many […]
Selecting out ridgelines from a DEM using ArcView 3x’s Spatial Analyst extension is pretty straightforward. These steps assume the initial DEM is called “elev”. Time Required: 10 minutes Here’s How: Compute a flow direction grid – a grid with codes indicating for each cell which of the eight possible directions […]