20-ha Human Utilization at 20-ha Resolution. Version 1.0, October 1995 Grid Name: uindex ----------------------------------------------------------------- ----------------------------------------------------------------- Identification Information Data Layer Name: 20-ha Human Utilization at 20-hectare resolution. Description: This is a map of human "utilization" in the Southern Appalachian Region. It was obtained by (1) convolving a land cover map (LC_SCAN) into a raster of discretized utilization scores, and (2) smoothing the scores by a median filter. For each pixel in the land cover map, the human utilization in the surrounding 20.25-ha (15x15 pixel) "window" was calculated and discretized into 255 classes. The result was mapped at 0.09-ha (1x1 pixel) resolution. This map was produced by applying a median filter in another 15x15 window, with a minimum mapping unit 20.25 ha, to the discretized map. Additional Keywords: Landscape ecology, satellite, Thematic Mapper. Citation: None. Native Data Set Environment: Unix; Arc/Info 7.02 (Grid) pathname: //uindex.e00.Z Scale: 450 meter cell size File Format: The data layer is a raster in one Arc/Info Grid file that has been exported using Arc/Info's "export" command and compressed using the unix "compress" utility. Use Restrictions: Data users must acknowledge Karl Hermann (University of Tennessee) and Larry Hayden (U.S. Forest Service) in all reports, publications, presentations, etc. Access Restrictions: None ----------------------------------------------------------------- ----------------------------------------------------------------- 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.: -420133.156 East Bounding Coord.: 353686.844 North Bounding Coord.: 730770.227 South Bounding Coord.: 16980.227 Distance Resolution: 450 meters Vertical Resolution: n/a ----------------------------------------------------------------- ----------------------------------------------------------------- Data Quality Information Thematic Accuracy: The utilization is based on the proportions of different land covers among 225 pixels in a calculation window. The statistic, a continuous [0,1] variable, was discretized into 255 classes in the range [1,255]; the class width is about 0.4 utilization units. Confidence: Unknown. Accuracy Method: n/a Horizontal Accuracy: n/a Vertical Accuracy: n/a Logical Consistency: Because the median filter operation changed the resolution of each pixel from 25 m to 450 m, there may be distortions near the east and south borders of the map. Because the calculations ignored any 'missing' pixels, there may be distortions near the boundaries of the Region. Completeness: There are no missing pixels within the Region. ----------------------------------------------------------------- ----------------------------------------------------------------- Source Information Source Material: LC_SCAN (land cover from Thematic Mapper images produced by Pacific Meridian Resources, Inc.; see separate metadata for LC_SCAN). Organization: Pacific Meridian Resources, Inc. Date: August 1995 Contribution: Land cover map Processing History Information Process Description: 1. Land cover map was received as an Arc/Info grid. The cell size was 25 m. 2. Reformatting: The grid was exported to ascii format using the Arc/Info GRIDASCII command, and then converted to an in-house format using an in-house tool. 3. The grid was subdivided into 64 overlapping sections. The overlap was 45 pixels to eliminate artificial 'edge' effects. 4. Human utilization intensity (proportion of non-forest and non-water clases) was mapped within each section using an in-house tool and a window size of 15x15 pixels. 5. The scores were median-filtered to a 15x15 pixel resolution within each section using an in-house tool. 6. The median-filtered sections were stitched back together, removing the overlap zones (3 pixels after median filtering). 7. Reformatting: The in-house format was converted to ascii format using an in-house tool, then imported into Arc/Info using the ASCIIGRID command, then exported using the EXPORT GRID command. Entity/Attribute Information Entity: Human utilization Definition: A raster map of a utilization statistic. Attributes: An 8-bit integer in the range [1,255], with zero (0) reserved for missing and background pixels. The value increases from 1 to 255 as the utilization statistic increases from 0 to 1. ----------------------------------------------------------------- ----------------------------------------------------------------- Status Information Data Set Status: Available Release Date: October 1995 ----------------------------------------------------------------- ----------------------------------------------------------------- Metadata Reference Information Date: October, 1995. Review Date: n/a Contact: Kurt Riitters (address below). ----------------------------------------------------------------- ----------------------------------------------------------------- Distribution Information Distribution Contact: Karl A. Hermann National Biological Service Cooperative University of Tennessee 17 Ridgeway Road Norris, TN 37828 (423)-632-1452 samab@utk.edu Distribution Liability: File Compression Technique: UNIX compress, Arc/Info export format Transfer Size: ----------------------------------------------------------------- ----------------------------------------------------------------- Contact Information Contact Person: Kurt Riitters Contact Mail Address: Tennessee Valley Authority Historic Forestry Building 17 Ridgeway Road, Norris TN 37828 USA Contact Phone: 423-632-1651 Contact Fax: n/a Contact email: n/a ----------------------------------------------------------------- -----------------------------------------------------------------