digital elevation model

A digital map of the elevation of an area on the earth. The data are either collected by a private party or purchased from an organization such as the U.S. Geological Survey (USGS) that has already undertaken the exploration of the area. Digital elevation models are gray scale images wherein the pixel values are actually elevation numbers. The pixels are also coordinated to world space (longitude and latitude), and each pixel represents some variable amount of that space (foot, meter, mile, etc.) depending on the purpose of the model and land area involved. See remote sensing and GIS glossary.

Sample Digital Elevation Model Rendering

This scene was rendered from a USGS digital elevation model of the Grand Canyon by the RiverTools application from Rivix, LLC, Broomfield, CO (www.rivix.com). RiverTools was written in IDL, a programming language from Research Systems, Inc. that is specialized for image processing and visualization. The black area is the Colorado River at the bottom of the canyon. The red is the immediate surrounding riverbank. (Image courtesy of Research Systems, Inc. and Rivix, LLC.)