.DT1 File Extension

Digital Terrain Elevation Data (DTED) Level 1 file used by military GIS programs to display terrain elevation data; contains a grid of elevation points that are uniformly spaced; used as a standard data set for military programs that require terrain elevation, slope, and surface contour information.

DTED Level 0 .DT0 and Level 2 .DT2 files also capture terrain elevation data. Level 0 files have the lowest terrain granularity, and Level 2 files have the highest terrain granularity. Level 1 data is at a resolution of three arc seconds, or approximately 100 meters.