Abstract
This collection (stacked series) of datasets is provided to the UVA Library's Scholars' Lab by the
University of Virginia's Mountain Lake Biological Station, and is provided AS-IS with no guarantees as regards to its
accuracy or temporal currency. It pertains primarily to the infrastructure, land cover and land use, and natural physical features
of MLBS and the surrounding region, for use in assisting on-going scientific research and education at MLBS.
The TEMPORAL EXTENT of the datasets in the datastack depend upon their source: MLBS-created (2000-2007), USFS (1997),
USCB (1995), USGS (variable), CAD survey data (1991), VAGAP (1999), Landsat (?), SPOT (?),
but some datasets may include attribute data from earlier periods.
For datasets derived from DEM data (elevation, slope, aspect, hillshading, derived hydrology and watershed basins, etc)
there are often two versions of the data; one covering a 6-quadrangle study area centered on MLBS, the other an extended
15-quadrangle area. Some of the other datasets derive from USFS-provided data (either from GWJ NF or from the JNF-Blacksburg
Ranger district), others from US Census TIGER 1995 data, others were created by MLBS researchers from survey data they
collected at MLBS. In the case of thematically-duplicated-but-not-identical datasets from different sources, a single
thematic description is provided (here in the abstract); see individual file listings for more info.
THEMATIC DATASETS/LAYERS included in this datastack (with non-exclusive list of included attributes):
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Mountain Lake Biological Station location.
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MLBS Trail System of named trails
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Mt. Lake Biological Station Pond
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Outline of the old Mt. Lake Golf Course
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Mountain Lake Biological Station AutoCAD Drawing (ca. 1991) - with buildings, trees, outcrops, utilities, etc.
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GPS Ground Control Points at MLBS
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USGS Salt Pond Benchmark
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Study area boundaries
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Boundaries of Craig, Giles, Montgomery and Monroe (WV) Counties
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USGS 7.5 minute topographic quadrangle boundaries
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Bear Cliffs location
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George Washington-Jefferson National Forest/Blacksburg Ranger District surface land ownership (USFS vs private inholdings) - incl. tract no.
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GWJNF administrative and district boundaries
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Forest Service management areas adjacent to the Appalachian Trail
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Jefferson NF old growth forest management areas
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JNF roadless areas
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JNF wilderness management areas
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Road networks (county/city, state, federal, forest service) - incl. limited geocoding/address matching info (tiger only)
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Railroads
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Major Utility Lines
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Regional Landmarks
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Rural and Urban Population Densities
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Populated Places (1995) of Blacksburg, Pearisburg, and Pembroke
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Peter's Mountain Ridge, WV
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Streams and Rivers - incl. intermittent or perennial status (tiger only)
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Open Water (ponds, lakes, wide rivers)
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Depressionless DEM elevation models - 30m resoultion, Z to nearest 1m
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100 meter interval Elevation Contours
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DEM-derived slopes
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DEM-derived aspects - in degrees or 8 cardinal directions
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DEM-derived hillshading
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DEM-derived flow accumulation
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DEM-derived flow direction
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DEM-derived Drainage basins
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DEM-derived Watershed boundaries
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DEM-derived Stream Networks
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VAGAP Landcover classes (33 categories)
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Landsat TM Scene
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SPOT PN panchromatic Scene
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HISTORY (Lineage):
MLBS Trail locations are based on raw GPS data collected by Eric Nagy.
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The GWJ National Forest themes were derived from Arc/Info coverages produced at 1:24000 scale by Blacksburg Ranger District.
Similar data sets were not available for the adjacent Monongahelia National Forest in West Virginia. GWJNF Datasets were
acquired from the George Washington and Jefferson National Forest GIS Database at http://svinet2.fs.fed.us/gwjnf/ftp. GWJNF
data was subsequently clipped with the study area extent and converted to shapefiles.
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The US Census county boundary, rivers and creeks, and roads coverages were derived from shapefile format 1:100,000 U.S.
Census Bureau TIGER/Line95 county data referenced to the North American Datum of 1983 (NAD83) in decimal degrees of
latitude/longitude and converted to NAD 27 UTM zone 17 N meters. Data was then clipped with the county boundary.
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Fifteen (or six) 1:24000 USGS quadrangle Digital Elevation Models (DEMs) were needed to cover Giles County
(or the more limited study area).
DEMS were acquired in Spatial Data Transfer Standard (SDTS) format from the U.S. Geological Survey website at
http://edcftp.cr.usgs.gov/pub/data/DEM/7.5min . The SDTS files were expanded using WinZip32 and converted
to DEM format with the stds2dem utility. The DEM files were imported into TNTmips and combined into a
single raster with the TNTmips Mosaic process and the bilinear interpolation method of resampling. Missing data
in the mosaicked raster were corrected using an SML script that identified "empty" cells and replaced their values
with an unweighted average of the eight-cell neighborhood. A depressionless elevation raster was created from
the corrected mosaic using the TNTmips Watershed process, then exported as an 8-bit unsigned raster in
ERDAS format. The ERDAS file was then converted to Arc/Info GRID format.
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The various slope, aspect, hillshaing, and watershed datasets were derived in a series of steps from the depressionless
elevation raster in Arc/Info GRID using topographic and hydrologic tools. The basins, watersheds, and streamnet grids were
subsequently converted to polygon coverages and then to shapefiles.
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The landcover map was completed by the Virginia Gap Analysis Project (VAGAP) and was obtained
from the digital library at the Virginia Tech Fish and Wildlife Information Exchange (VT-FWIE). The landcover raster was
converted to Arc/Info GRID format and then clipped with the county boundary polygon.
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The 30m resolution Landsat Thematic Mapper (TM) six-band composite image was obtained from VT-FWIE. The ERDAS format file was
imported into TNTmips and all six bands were clipped with the study area boundary polygon using the TNTmips Extract-by-Vector
process. The clipped six-band composite image was exported back into ERDAS format.
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Two SPOT scenes were needed to cover the MLBS study area. The 10m resolution SPOT Panchromatic (PN) single-band images
were obtained from VT-FWIE. The ERDAS format files were imported into TNTmips and clipped with the study area boundary
polygon using the TNTmips Extract-by-Vector process. The clipped images were combined with the TNTmips Mosaic process
and the cubic convolution method of resampling. The single-band mosaicked image was exported back into ERDAS format.