Identification Information
Data Quality Information
Spatial Data Organization Information
Spatial Reference Information
Entity and Attribute Information
Distribution Information
Metadata Reference Information
Description:
This monochromatic image file represents shaded relief of landforms of the COHYST area.
Hill-shading is presented in shades of gray. To view this image geo-reference the land.tfw must be used.
The image is tended t render the shape of the area terrain in a visully intuitive manner.
Theme Keyword: Topographic Data, shaded relief Browse Graphic:
Browse Graphic File Name:
COHYST's Shaded Relief(small)
Browse Graphic File Description:
Low resolution view of statewide shaded relief image. Projected at State Plane NAD83.
Browse Graphic File Type: TIF
Use Restrictions:
This image is intended for cartographic reference purposes in the COHYST Study and may not be
suitable for some quantitative analyses.
Access Limitations:
None, the source data are in the public-domain so that this product can be freely distributed to others.
Native Data Set Environment:
Attribute Accuracy: n/a
Attribute Accuracy Explanation: n/a
Logical Consistency Report: n/a
Completeness Report:
Coverage provided for the COHYST Study area.
Horizontal Positional Accuracy: n/a
Horizontal Positional Accuracy Explanation:
Positional accuracy has not been determined.
Vertical Positional Accuracy: +/- 30 m
Vertical Positional Accuracy Explanation:
The vertical RMSE statistic is used to describe the vertical accuracy of a DEM,
encompassing both random and systematic errors introduced during production of
the data. The RMSE is encoded in element number 5 of record C of the DEM. Accuracy
is computed by a comparison of linear interpolated elevations in the DEM with
corresponding known elevations. Test points are well distributed, representative of
the terrain, and have true elevations with accuracies well within the DEM accuracy criteria.
Acceptable test points include, in order of preference: field control, aerotriangulated
test points, spot elevations, or points on contours from existing source maps with
appropriate contour interval. A minimum of 28 test points per DEM is required to compute
the RMSE, which is composed of a single test using 20 interior points and 8 edge points.
Edge points are those which are located along, at, or near the quadrangle neatlines and are
deemed by the editor to be useful to evaluating the accuracy of the edge of the DEM.
Collection of test point data and comparison of the DEM with the quadrangle hypsography
are conducted by the quality control units within the USGS.
There are three types of DEM vertical errors; blunder, systematic and random. These errors
are reduced in magnitude by editing but cannot be completely eliminated. Blunder errors are
those errors of major proportions and are easily identified and removed during interactive
editing. Systematic errors are those errors that follow some fixed pattern and are introduced
by data collection procedures and systems. These error artifacts include: vertical elevation
shifts, misinterpretation of terrain surface due to trees, buildings and shadows, and fictitious
ridges, tops, benches or striations. Random errors result from unknown or accidental causes.
DEM's are edited to correctly depict elevation surfaces that correspond to water bodies of specified
size. contour interval, determined by the source map, is the maximum permitted. Systematic
errors may not exceed one contour interval, determined by the source map, is the maximum
permitted. Systematic errors may not exceed one contour interval specified by the source graphic.
Level 2 DEMs have been processed or smoothed for consistency and edited to remove identifiable
systematic errors. Level-2 DEMS have better resolution that Level-1 DEMS.
Level 1 DEM: A RMSE of 7-meters or less is the desired accuracy standard. A RMSE of 15-meters is
the maximum permitted. A 7.5-minute DEM at this level has an absolute elevation error tolerance
of 50 meters (approximately three times the 15-meter RMSE) for blunder errors for any grid node
when compared to the true elevation. Any array of points in the DEM can not encompass more than
49 contiguous elevations in error by more than 21 meters (three times the 7-meter RMSE). Systematic
errors that are within stated accuracy standards are tolerated.
Source Information:
Source Date: n/a
Source Distance Resolution (feet):
Process Description:
The Shaded Relief of COHYST area is a array of 30-meter DEM's. DEM file were
mosaic array to create a grid of the COHYST area. Using the ARC/Info GRID command HILLSHADE
to create the tif image.
Direct Spatial Reference Method: Raster
Raster Object Information:
Rastor Object Typet: Pixel
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Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: State Plane Coordinate System 1983
State_Plane_Coordinate_System:
SPCS_Zone_Identifier: Nebraska
Lambert_Conformal_Conic:
Standard_Parallel: 40.000000
Standard_Parallel: 43.000000
Longitude_of_Central_Meridian: -100.000000
Latitude_of_Projection_Origin: 39.833333
False_Easting: 1640416.666500
False_Northing: 0.000000
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Coordinate pair
Coordinate_Representation:
Abscissa_Resolution:
Ordinate_Resolution:
Planar_Distance_Units:
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: GRS 80
Semi-major_Axis: 20925604.4720406
Denominator_of_Flattening_Ratio: 298.26
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Attribute Label: n/a
Attribute Definition Source: n/a
Entity and Attribute Detail Citation: n/a
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Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Nebraska Department of Natural Resources
Contact_Person: Richard Vollertsen
Contact_Position: Database Manager
Contact_Address:
Address_Type: mailing and physical address
Address: 301 Centennial Mall South
City: Lincoln
State_or_Province: NE
Postal_Code: 68509-4676
Country: USA
Contact_Voice_Telephone: 402-471-3951
Contact_Facsimile_Telephone: 402-471-2900
Contact_Electronic_Mail_Address: rvollertsen@dnr.state.ne.us
Hours_of_Service: 8AM-5PM
Resource_Description:
Distribution_Liability:
No warranty expressed or implied is made by the Nebraska
Department of Natural Resources or the Platte River
Cooperative Hydrology Study.
Standard Order Process:
Data are available through anonymous ftp and the World Wide Web at the ftp
address and URL address listed under Distributor.
File Decompression Technique:
Image file was compressed with WINZIP, then made into a executable file.
Transfer Size: 82 Mb in WINZIP executable format; 204 Mb in uncompressed tif format
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Metadata_Date: 2002
Metadata_Review_Date: 2003
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Nebraska Department of Natural Resources
Contact_Person: Richard Vollertsen
Contact_Position: Database Manager
Contact_Address:
Address_Type: Mailing and physical address
Address: 301 Centennial Mall South
City: Lincoln
State_or_Province: NE
Postal_Code: 68509-4676
Country: USA
Contact_Voice_Telephone: 402-471-3951
Contact_Facsimile_Telephone: 402-471-2900
Contact_Electronic_Mail_Address: rvollertsen@dnr.state.ne.us
Hours_of_Service: 8AM-5PM
Metadata_Standard_Name: n/a
Metadata_Standard_Version: n/a
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