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Read U. S. Department of Defense Digital Terrain Elevation Data (DTED) data
Syntax
[map,maplegend] = dted [map,maplegend] = dted(filename) [map,maplegend] = dted(filename,scalefactor) [map,maplegend] = dted(filename,scalefactor,latlim,lonlim) [map,maplegend,UHL,DSI,ACC] = dted(...)
Background
The U. S. Department of Defense, through the National Imagery and Mapping Agency, produces several kinds of digital cartographic data. One is digital elevation data, in a series called DTED, for Defense Digital Terrain Elevation Data. The data is available as 1-by-1 degree quadrangles at horizontal resolutions ranging from about 1 kilometer to 1 meter. The lowest resolution data is available to the public. Higher resolution data is restricted to the U.S. Department of Defense and its contractors.
Description
DTED Read U.S. DoD Digital Terrain Elevation Data (DTED) data.
[map,maplegend] = dted returns all of the elevation data in a DTED file as a regular matrix map with elevations in meters. The file is selected interactively. This function reads the DTED elevation files, which generally have filenames ending in ".dtN", where N is 0,1,2,3,... .
[map,maplegend] = dted(filename) returns all of the elevation data in the specified DTED file. The file must be found on the MATLAB path. If not found, the file may be selected interactively.
[map,maplegend] = dted(filename,scalefactor) returns data from the specified DTED file, downsampled by the scalefactor. If omitted, a scalefactor of 1 is assumed.
[map,maplegend] = dted(filename,scalefactor,latlim,lonlim) reads the data for the part of the DTED file within the latitude and longitude limits. The limits must be two-element vectors in units of degrees.
[map,maplegend] = dted(dirname,scalefactor,latlim,lonlim) reads and concatenates data from multiple files within a DTED CD-ROM or directory structure. The dirname input is a string with the name of a directory containing the DTED directory. Within the DTED directory are subdirectories for each degree of longitude, each of which contain files for each degree of latitude. For DTED CD-ROMs, dirname is the device name of the CD-ROM drive.
[map,maplegend,UHL,DSI,ACC] = dted(...) also returns the DTED User Header Label (UHL), Data Set Identification (DSI) and Accuracy (ACC) metadata records as structures. Documentation describing the meaning of these records is available online at http://www.nima.mil/publications/specs/printed/DTED/dted1-2.doc.
Examples
[map,maplegend] = dted('n38.dt0'); [map,maplegend,UHL,DSI,ACC] = dted('n38.dt0',1,[38.5 38.8],... [-76.8 -76.6]); [map,maplegend,UHL,DSI,ACC] = dted(`f:',1,[38.5 38.8],... [-76.8 -76.6]);
Limitations
At higher latitudes the files have fewer longitude records. In those cases a warning is issued, and the coarser spacing is used in both directions.
Remarks
This function reads the DTED elevation files in the format used for files delivered on CD-ROM. The file names generally end in ".dtN", where N is 0,1,2,3,etc.
The 1 kilometer data is available online at http://www.nima.mil/geospatial/products/DTED/dted.html
The higher resolution data is available to the U.S. Department of Defense and its contractors from the National Imagery and Mapping Agency (NIMA).
DTED0 files have 120x120 points. DTED1 files have 1201x1201. The edges of adjacent tiles have redundant records. Maps will extend a half a cell outside the requested map limits.
A third-party description of the DTED data may be found at
http://www.fas.org/irp/program/core/dted.htm
Detailed official documentation is available at
http://www.nima.mil/publications/specs/printed/DTED/dted1-2.doc.
The DTED files are binary. No line ending conversion or byte-swapping is required.
See Also
usgsdem |
USGS 1-Degree (3-arc-sec resolution) digital elevation data |
gtopo30 |
30-Arc-Sec global digital elevation data |
tbase |
TerrainBase Global 5-Min digital terrain data |
etopo5 |
ETOPO5 Global 5-Min digital terrain data |
| | demdataui | dteds | |