In support of military applications, the National Geospatial-Intelligence Agency (NGA) has developed standard digital datasets (Digital Terrain Elevation Data (DTED)) which is a uniform matrix of terrain elevation values which provides basic quantitative data for systems and applications that require terrain elevation, slope, and/or surface roughness information. DTED Level 0
elevation post spacing is 30 arc second (nominally one kilometer). DTED Level 0 was derived from NGA DTED Level 1 to support a federal agency requirement. It was then determined that DTED Level 0 could be made available (within copyright restrictions) to the public at no charge through the Internet. Support from select international mapping organizations was instrumental in the generation of the Level 0 dataset. The following nations have contributed data to this effort: Belgium, Denmark, France, Germany, Italy, Netherlands, Norway, Spain, and the United Kingdom. DTED Level 0 may be of value to scientific, technical, and other communities for and applications that require terrain elevation, slope, and/or surface roughness information. It allows a gross representation of the Earth's surface for general modeling and assessment activities. Such reduced resolution data is not intended and should not be used for automated flight guidance or other precision activity involving the safety of the public.
DTED Level 1 is the basic medium resolution elevation data source for all military activities and systems that require landform, slope, elevation, and/or gross terrain roughness in a digital format. DTED Level 1 is the basic medium resolution elevation data source for all military activities and systems that require landform, slope, elevation and/or terrain roughness in a digital format. DTED Level 1 is a uniform matrix of terrain elevation values with post spacing every 3 arc seconds (approximately 100 meters). The information content is approximately equivalent to the contour information represented on a 250,000 scale map.
DTED Level 2 (30m) will be available thru the 2000 STS-99 Shuttle IFSAR mission in 2001. DTED Level 2 is the basic high resolution elevation data source for all military activities and systems that require landform, slope, elevation, and/or terrain roughness in a digital format. DTED Level 2 is a uniform gridded matrix of terrain elevation values with post spacing of one arc second (approximately 30 meters). Due to extremely sparse area coverage there is no catalog listing for DTED Level 2. The information content is equivalent to the contour information represented on a 1: 50,000 scale map.
Distribution of DTED and the Digital Data Products catalog is authorized to the Department of Defense, U.S. DOD contractors, and to U.S. Government agencies that support DOD functions (by authority of the Director, National Geospatial-Intelligence Agency, 30 May 1990).
NGA has started to develop a strategy to understand and meet the increasing custom demand for higher resolution digital elevation data (DTED). Currently, several private contractors state that they have the capability to collect and generate high resolution elevation data. NGA is designing a specification to evaluate and test this data when it is made available. Associated with this development, selective customers will be interviewed to better understand their particular needs for this information. Another problem with this higher resolution data is capability with lower data, such as DTED Levels 1 and 2. Current DTED format does not handle the higher resolution data very well, since the finest resolution that can be implemented is 0.1 arc-second. Below is a summary of known and proposed post spacing, rows and columns, and tile size.