Arc/Info version 7.0.3,
Pathname =
Attribute_Accuracy
Attribute_Accuracy_Report:
See Vertical Accuracy.
Logical_Consistency_Report:
None
Completeness_Report:
None
Positional_Accuracy
Horizontal_Positional_Accuracy
Horizontal_Positional_Accuracy_Report:
90 percent probability of 300m accuracy.
Vertical_Positional_Accuracy
Vertical_Positional_Accuracy_Report:
90 percent probability of 300m accuracy.
See also: http://nsdi.usgs.gov/nsdi/wais/maps/dem1deg.HTML.
and http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem.
Lineage
Source_Information
Source_Citation
Citation_Information
Originator: Defense Mapping Agency
Publication_Date: 19750101
Title: 1-degree Digital Elevation Models
Geospatial_Data_Presentation_Form: map
Publication_Information
Publication_Place: Reston, VA
Publisher: U.S. Geologic Survey
Source_Scale_Denominator: 250000
Type_of_Source_Media: Unknown
Source_Time_Period_of_Content
Time_Period_Information
Single_Date/Time
Calendar_Date: 19500101
Source_Currentness_Reference: Publication Date
Source_Citation_Abbreviation: dma
Source_Contribution:
The data set was derived from this source.
Process_Step
Process_Description:
The first step in producing the image was the creation of a statewide
digital elevation model (DEM) using data produced in 1degree x 1degree blocks
by the Defense Mapping Agency Topographic Center. These same data are currently
available from the Earth Science Information Center.
The original DEMs have a resolution of 3x6 arc-seconds in the horizontal
(approximately 90x90 m); vertical values were interpolated to the nearest meter
from digitized 200-ft contour. The 1-degree x 1-degree blocks were spliced together
in 1:250,000-scale quadrangles, most of which are 1-degree x 3-degree. Visible flaws
in the spliced data set were repaired using techniques such as data inversion,
replacement of missing data lines, and correction of geometric distortions. The
individual quadrangle data sets (153 quadrangles) were then sampled at a spacing of
30x30 arc-seconds (a ground resolution of approximately 900x450 m). Several
remaining omissions in the data were filled using hyposography from the Digital
Chart of the World (Defense Mapping Agency, 1992) together with surrounding DEM data.
This patched data set was reprojected and interpolated using a bilinear resampling
method to form a statewide data set in Albers Equal-Area Conic projection having a
grid-cell size of 300m. The final step in generating the based DEM was to delimit
the elevation data at sea level by adding a coastline digitized from 1:250,000-scale
USGS quadrangles. This 300-m data set achieves a degree of resolution suitable for
the creation of a sharp high-resoluytion shaded-relief image at 1:2,500,000 scale.
Data processing were preformed by Mike Fleming, USGS EROS Alaska Field Office.
Process_Date:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information
Raster_Object_Type: Point
Row_Count: 8372
Column_Count: 11503
Horizontal_Coordinate_System_Definition
Planar
Map_Projection
Map_Projection_Name: Albers Conical Equal Area
Albers_Conical_Equal_Area
Standard_Parallel: 55.0
Standard_Parallel: 65.0
Longitude_of_Central_Meridian: -154.0
Latitude_of_Projection_Origin: 50.0
False_Easting: 0.00000
False_Northing: 0.00000
Planar_Coordinate_Information
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation
Abscissa_Resolution: 64
Ordinate_Resolution: 64
Planar_Distance_Units: meters
Geodetic_Model
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.4
Denominator_of_Flattening_Ratio: 294.98
Vertical_Coordinate_System_Definition
Altitude_System_Definition
Altitude_Datum_Name: NGVD29
Altitude_Resolution: 1
Altitude_Distance_Units: METERS
Altitude_Encoding_Method: Implicit coordinate
Distributor
Contact_Information
Contact_Organization_Primary
Contact_Organization: U.S. Geological Survey EROS Alaska Field Office
Contact_Person:
Contact_Position:
Contact_Address
Address_Type: mailing and physical address
Address: 4230 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508-4664
Country: USA
Contact_Voice_Telephone: (907) 786-7020
Contact_Facsimile_Telephone: (907) 786-7036
Contact_Electronic_Mail_Address: agdcweb@usgs.gov
Hours_of_Service: Monday-Friday, 8-5, Alaska Standard Time
Distribution_Liability: Users must assume responsibility to determine the
usability of this data for their purposes.
Metadata_Date: 19970512
Metadata_Review_Date: 19970512
Metadata_Contact
Contact_Information
Contact_Organization_Primary
Contact_Organization: U.S. Geological Survey EROS Alaska Field Office
Contact_Person:
Contact_Address
Address_Type: mailing and physical address
Address: 4230 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508-4664
Country: USA
Contact_Voice_Telephone: (907) 786-7020
Contact_Facsimile_Telephone: (907) 786-7036
Contact_Electronic_Mail_Address: agdcweb@usgs.gov
Hours_of_Service: Monday-Friday, 8-5, Alaska Standard Time
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: 19940608