DTED

DTED (or Digital Terrain Elevation Data) is a standard of digital datasets which consists of a matrix of terrain elevation values. This standard was originally developed in the 1970s to support aircraft radar simulation and prediction.

DTED supports many applications, including line-of-sight analyses, terrain profiling, 3-D terrain visualization, mission planning/rehearsal, and modeling and simulation. DTED is a standard National Geospatial-Intelligence Agency (NGA) product that provides medium resolution, quantitative data in a digital format for military system applications that require terrain elevation.

The DTED format for level 0, 1 and 2 is described in U.S. Military Specification Digital Terrain Elevation Data (DTED) MIL-PRF-89020B, and amongst other parameters describes the resolution for each level:


 * Level 0 has a post spacing of 30 arc seconds in latitude direction (ca. 900 meters).
 * Level 1 has a post spacing of ca. 90 meters which results in the following table:


 * Level 2 has a post spacing of 1 arcsecond (ca. 30 meters).

In addition three more levels (3, 4 and 5) at increasing resolution have been proposed, but not yet standardized.

DTED data is stored in a big endian format where negative numbers are signed magnitude.