Steeves, Peter and Douglas Nebert; modified by, 19948, Snake/Salt River Basin Plan - Huc 4 Boundaries: U.S. Geological Survey; University of Wyoming WyGISC, Reston, Virginia; Laramie, Wyoming.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1927.
The ellipsoid used is Clarke 1866.
The semi-major axis of the ellipsoid used is 6378206.400000.
The flattening of the ellipsoid used is 1/294.978698.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
USGS Water Resources Division; Tom Kohley, U. of Wyoming
U.S. Geological Survey, Water Resources Div. (WRD)
c/o Mark Negri
Computer Specialist, Spatial Data Support Unit
12201 Sunrise Valley Drive, MS-445
Reston, VA 20191
USA
703-648-5613 (voice)
703-648-5295 (FAX)
mnegri@usgs.gov
- Hours_of_Service: 6:30am-3:30pm EST
- Contact_Instructions: May contact thru email or telephone
The HUC dataset was compiled originally to provide the National Water Quality Assessment (NAWQA) study units with an intermediate- scale river basin boundary for extracting other GIS data layers. The data can also be used for illustration purposes at intermediate or small scales (1:250,000 to 1:2 million). This modified dataset was produced under contract with the Wyoming Game and Fish Department for the purpose of wildlife habitat prioritization in Wyoming.
Survey, US Geological , unknown, GIRAS.
NOTE - this shapefile was clipped to the Snake/Salt Basin Boundary and reprojected as part of the Wyoming Water Plan.
Data sources used in this process:
Data sources used in this process:
Data sources used in this process:
Label point accuracy was checked by making a point cover of polygon labels from the 1:2,000,000 HUC coverage and then doing an identify of those points in the 1:250,000 scale HUC polygon. This procedure looked for both new or missing polygons, and was also used to check attribute values. Both coverages were also dissolved by accounting unit and comparisons made of the number and location of remaining polygons and corrections made.
The line work for the HUC coverage was checked against the line work from: (1) the 1:2,000,000 HUC coverage by plotting both data sets out on one large graphic (about 1:3,000,000). No major discrepancies were found except in coastal areas where the 1:2,000,000 scale coverage had more detail than the 1:250,000 scale coverage. (2) line work from 1:24,000 scale digitized drainage basins in Colorado, Illinois, and New Jersey. The match was generally good with departures generally less than 2500 meters. The biggest departures were in Colorado and were as large as 4000 meters. (3) line work from the 1:2,000,000 scale rivers coverage for the USA by plotting both data sets out on one large graphic (about 1:3,000,000). In general the nesting of streams in HUCs was good and HUC boundaries intersected steams at stream intersections. (4) line work from 1:100,000 scale streams from Colorado, Illinois, and Kansas. The nesting of streams in HUCs was very good. Stream arcs for the most part did not cross HUC arcs except at stream intersections. The error (distance from intersection to HUC line) between HUC lines and stream intersection was less than 500 meters at all intersections checked (about 25).
complete to USGS level four hydrologic unit code
Polygon and chain-node topology present.
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints:
- These data were digitized at a scale of 1:250,000 and use of these boundaries with larger scale data (i.e. 1:24k hydrography) is not recommended as it would be beyond the resolution capabilities of the data set. Although the boundaries of the hydrologic units were modified to best match the 1:100,000 scale surficial hydrography DLG, these data should not be considered a 1:100,000 scale product.
WyGISC
c/o Data Manager
Box 4008 University Station
Laramie, Wyoming 82071
USA
307-766-2735 (voice)
n/a
Downloadable Data
The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate used described in this metadata document.
Data format: | ARCE (Arc/Info export) (version 7.0.4) Size: 0.168 |
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Network links: |
ftp.sdvc.uwyo.edu or <http://www.sdvc.uwyo.edu/clearinghouse> |
No fees are required for downloading the data that is on-line. Some fees may be required to cover costs of tapes if data is required on tape media.
WyGISC
c/o Margo Berendsen
Box 4008 University Station
Laramie, Wyoming 82071
USA
307-766-2735 (voice)
meh@uwyo.edu
- Contact_Instructions: <http://www.sdvc.uwyo.edu/>