Digital Terrain Elevation Data (DTED) Level 0 file used by GIS programs to study terrain elevation data; contains a matrix of elevation points that are uniformly spaced; used by scientific, technical, and other communities to study the slope, elevation, and surface roughness of global terrains.
DTED Level 1 .DT1 and Level 2 .DT2 files also contain terrain data at increasing resolution. Level 0 files have the lowest resolution data with grid points spaced at 30 arc seconds, or roughly one kilometer.
The DTED Level 0 data set was contributed by a coalition of countries, including Belgium, Denmark, France, Germany, Italy, Netherlands, Norway, Spain, and the United Kingdom. The data set is freely available.