Data Set Title / Coverage Name: SAA Digital Elevation Model Derived from DMA 3 ARC SECOND DEM SAA Version 3.0 Version Date: 3/21/96 ---------------------------------------------------------------- ---------------------------------------------------------------- Identification Information Data Layer Name: dem_3s Description: Digital Elevation Model in the vicinity of the Southern Appalachian Assessment Study Area Study Area (Derived from DMA 3 ARC Second DEM) Keywords: SAA, Southern Appalachian Assessment, elevation, topography, digital elevation model DEM Citation: This data set was initially developed through a series of procedures conducted by the Defense Mapping Agency, Topographic Center (DMATC) and the National Telecommunications and Information Administration (NTIA). Native Data Set Environment: UNIX; ARC/INFO 7.0.3 pathname: Scale: 1:250,000 File Format: ARC/INFO 7.0.3 GRID Coverage Use Restrictions: Access Restrictions: ---------------------------------------------------------------- ---------------------------------------------------------------- Spatial Reference Information Datum: North American Datum 1983 (NAD83) Precision: single Projection: Albers Equal Area Units: meters Spheroid: WGS-84 1st Std Parallel: 34 00 00 2nd Std Parallel: 38 00 00 Central Meridian: -82 00 00 Origin: 33 00 00 False Northing: 0.0 False Easting: 0.0 Extent: West Bounding Coord.: -428494.531 East Bounding Coord.: 359406.682 North Bounding Coord.: 739777.944 South Bounding Coord.: 10325.824 Distance Resolution: Vertical Resolution: ---------------------------------------------------------------- ---------------------------------------------------------------- Data Quality Information Thematic Accuracy: unknown Confidence: unknown Accuracy Method: unknown Horizontal Accuracy: unknown Confidence: unknown Accuracy Method: unknown Vertical Accuracy: n/a Logical Consistency: This data set is based on the 1-degree Digital Elevation Models produced by DMATC. The 1-degree Digital Elevation Models are reported in USGS Data Users Guide 5 to adequately support computer applications that analyze hypsographic features to a level of detail similar to manual interpretations of information as printed at map scales not larger than 1:250,000. Completeness: ---------------------------------------------------------------- ---------------------------------------------------------------- Source Information Source Material: 3 arc-second digital elevation data. Organization: US Geological Survey, EROS Data Center Date: Distance Resolution: 3 arc-seconds Contribution: Elevation values. Source Material: Organization: Date: Distance Resolution: unknown Contribution: --------------------------------------------------------------- --------------------------------------------------------------- Processing History Information The history of the DEM processing follows: 1. The data set distributed by USGS is described in this section. The 3-second point topography data set was developed through a series of processing procedures conducted by the Defense Mapping Agency, Topographic Center (DMATC) and the National Telecommunications and Information Administration (NTIA). These procedures are briefly outlined in the following paragraphs. The 3-second digital topographic database is called Digital Terrain Data. DMATC developed this 3-second file by digitizing topographic contour lines and geographic features from printing plates that were used to produce the 1:250,000 scale U.S. Geological Survey Topographic maps. The digitized elevation contours were then converted into grids of interpolated elevations, with a single value given for every 3" x 3" coordinate cell. These values corresponded to the elevation given for a point situated in the center of each cell. Elevation data were rounded to the nearest 20 foot interval. 2. According to the USGS Data Users Guide 5 the 1-degree elevation models from which this data set originated the array of elevations is referenced horizontally on the geographic (latitude/longitude) coordinate system of the World Geodetic System 1972 Datum (WGS 72) or the World Geodetic System of 1984 (WGS 84). Appendix H of the same guide states "All DMA DEM's and DTED's lacking datum descriptors are WGS 72." There being no datum descriptor included in this data set it is assumed the datum is WGS 72. 3. The WGS 72 datum was assumed to be functional equivalent to the NAD83. Processing was performed by Karl A. Hermann, National Biological Service Cooperative at the University of Tennessee. The 1 degree by 1 degree DMA 3 arc second DEMs were ftp'ed from the USGS EROS Data Center, reformatted for use on a SUN workstation, and converted to ARC/INFO GRIDs with the DEMLATTICE program. The GRIDs were then merged together with the ARC/INFO LATTICEMERGE program. The final step was a projection to the SAA Albers projection and coordinate system. A default cellsize of 92.924 meters was used. ---------------------------------------------------------------- ---------------------------------------------------------------- Entity/Attribute Information Entity: DEM_3S.VAT Definition: 92.924 meter cells for elevation values Attributes: VALUE - elevation (MSL) in meters Entity: Definition: Attributes: Entity: Definition: Attributes: ---------------------------------------------------------------- ---------------------------------------------------------------- Status Information Data Set Status: Available Release Date: 3/21/96 ---------------------------------------------------------------- ---------------------------------------------------------------- Metadata Reference Information Date: 3/20/96 Review Date: Contact: Karl A. Hermann National Biological Service Cooperative University of Tennessee 17 Ridgeway Road Norris, TN 37828 samab@utk.edu (423)-632-1452 ---------------------------------------------------------------- ---------------------------------------------------------------- Distribution Information Distribution Contact: Karl A. Hermann National Biological Service Cooperative University of Tennessee 17 Ridgeway Road Norris, TN 37828 samab@utk.edu (423)-632-1452 Distribution Liability: File Compression Technique: UNIX compress, Arc/Info export format Transfer Size: --------------------------------------------------------------- --------------------------------------------------------------- Contact Information Contact Person: Karl A. Hermann Contact Mail Address: National Biological Service Cooperative University of Tennessee 17 Ridgeway Road Norris, TN 37828 Contact Phone: (423)-632-1452 Contact Fax: (423)-632-1612 Contact email: samab@www.lib.utk Home Page for Updates: http://www.lib.utk.edu/samab ---------------------------------------------------------------- ----------------------------------------------------------------