ABSTRACT
Elevation, as a measurement of topography (one of Earth’s most fundamental geophysical properties), is often a key variable in Earth science studies. Because of its importance in the Earth sciences, topography has been widely represented by regularly spaced measurements across the land surface in the form of digital elevation models (DEMs). Elevation data are collected with a number of methods, including surveys conducted at ground level, as well as with remote-sensing techniques from both airborne and spaceborne platforms. Remote-sensing techniques used to collect topographic information include stereo-optical imagery, interferometric synthetic aperture radar (InSAR), radar altimetry, and laser altimetry (or light detection and ranging [LiDAR]). Elevation models derived from these approaches often are used together to develop global DEMs for Earth science studies, and the important differences (and similarities) among elevation measurements from the differing remote-sensing methods must be well understood. Satellite remote sensing is an ideal method for collecting data suitable for the development of global elevation models at a range of resolutions over broad areas. Spaceborne systems have the advantage of acquiring consistent quality data over the globe. Future prospects are excellent for a better understanding of existing data and for the collection of new data suitable for improving global DEMs.
