USGS 1:250,000 DIGITAL ELEVATION MODEL

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: UNITED STATES GEOLOGICAL SURVEY

Publication_Date: 19840000

Title: USGS 1:250,000 DIGITAL ELEVATION MODEL

Edition: 20010000

Geospatial_Data_Presentation_Form: raster digital data

Online_Linkage: <http://www.usgs.gov>

Description:

Abstract:

This dataset contains a Digital Elevation Model (DEM). The USGSDEM is an ARC/INFO grid that consists of 92 meter cells whose values represent elevation relative to sea level. These floating point values enable us to display a continuous surface of elevation, as opposed to topography which is broken into intervals.

Purpose:

This dataset contains a Digital Elevation Model (DEM). The USGSDEM is an ARC/INFO grid that consists of 92 meter cells whose values represent elevation relative to sea level. These floating point values enable us to display a continuous surface of elevation, as opposed to topography which is broken into intervals. The cell values for this grid represent elevation in meters. DEM's may be used to do the following types of analysis: hydrologic analysis including flow direction, flow accumulation, and watershed delineation; and determination of slope and aspect, and analytical hillshading.

For more information, consider the following resources:

Jenson, S.K. and J.O. Domingue. 1988. Extracting Topographic Structure from Digital Elevation Data for Geographic Information System Analysis. Photogrammetric Engineering and Remote Sensing. 54(11) 1593-1600.

Philip, G.M. and D.F. Watson. 1982. A Precise Method for Determining Contoured Surfaces. Australian Petroleum Exploration Association Journal 22: 205-212.

A good source of information regarding this USGS Digital Elevation Model can be found Online at: <http://rmmcweb.cr.usgs.gov/elevation/dpi_dem.html>

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19720000

Ending_Date: 19840000

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: Irregular

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -87.429040

East_Bounding_Coordinate: -79.872251

North_Bounding_Coordinate: 30.983191

South_Bounding_Coordinate: 24.492815

Keywords:

Theme:

Theme_Keyword_Thesaurus: NONE

Theme_Keyword: UNITED STATES GEOLOGICAL SURVEY

Theme_Keyword: Digital Elevation Model

Theme_Keyword: DEM

Theme_Keyword: USGS

Theme_Keyword: DRG

Theme_Keyword: model

Theme_Keyword: Elevation

Theme_Keyword: conservation

Theme_Keyword: topography

Theme_Keyword: Planning

Place:

Place_Keyword_Thesaurus: NONE

Place_Keyword: Florida

Place_Keyword: Southeast United States

Place_Keyword: Southeast U.S

Temporal:

Temporal_Keyword_Thesaurus: NONE

Temporal_Keyword: 1980s

Temporal_Keyword: 1990s

Access_Constraints: NONE

Use_Constraints:

THE DATA INCLUDED IN THIS APPLICATION ARE BASED ON INTERPRETATION OF AVAILABLE INFORMATION AND SHOULD NOT BE CONSTRUED AS LEGALLY BINDING.

Scale is an important factor in data usage. Certain scale data sets are not suitable for some projects, analysis, or modeling purposes. Please be sure you are using the best available data.

1:24000 scale data sets are recommended for projects that are at the county level. 1:24000 data should NOT be used for high accuracy base mapping such as property parcel boundaries.

1:100000 scale data sets are recommended for projects that are at the multi-county or regional level. 1:250000 scale data sets are recommended for projects that are at the regional or state level or larger.

DEM's may be used in the generation of three-dimensional graphics displaying terrain slope, apsect (direction of slope), and terrain profiles between selected points. At the USGS, DEM's have been used in combination with digital raster graphics (DRG's), digital line graphs (DLG's), and digital orthophoto quadrangles (DOQ's) to both enhance the visual information for data extraction and revision purposes and to create aesthetically pleasing and dramatic hybrid digital images. Non-graphic applications such as modeling terrain and gravity data for use in the search for energy resources, calculating the volume of proposed reservoirs, and determining landslide probability have also been developed

Native_Data_Set_Environment:

For more information, visit: <http://rmmcweb.cr.usgs.gov/elevation/dpi_dem.html>

Cross_Reference:

Citation_Information:

Originator: UNITED STATES GEOLOGICAL SURVEY

Publication_Date: 19840000

Title: Unavailable

Geospatial_Data_Presentation_Form: Map

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

A DEM file is organized into a series of three records, A, B, and C. The A record contains information defining the general characteristics of the DEM, including its name, boundaries, units of measurement, minimum and maximum elevations, number of B records, and projection parameters. Each B record consists of an elevation profile with associated header information, and the C record contains accuracy data. Each file contains a single A and C record, while there is a separate B record for each elevation profile. More detailed information about the organization of a DEM file can be found in the National Mapping Program Technical Instructions, Standards for Digital Elevation Models and Digital Elevations Models: Data User's Guide.

Logical_Consistency_Report:

Certain node/geometry and topology (GT)-polygon/chain relationships are collected or generated to satisfy topological requirements. Some of these requirements include: chains must begin and end at nodes, chains must connect to each other at nodes, chains do not extend through nodes, left and right GT-polygons are defined for each chain element and are consistent throughout the transfer, and the chains representing the limits of the file (neatline) are free of gaps. The neatline is generated by connecting the four corners of the digital file, as established during initialization of the digital file. All data outside the enclosed region are ignored and all data crossing these geographically straight lines are clipped at the neatline. (Exception: During the QA/QC process all data is examined and if errors are found and corrections are possible, then data is corrected accordingly. This process is documented in the Process_Step.) Data within a specified tolerance of the neatline are snapped to the neatline. Neatline straightening aligns the digitized edges of the digital data with the generated neatline, that is, with the longitude/latitude lines in geographic coordinates. All internal polygons are tested for closure. Certain attributes and/or entities, e.g. closure line, convey data quality information. When information to be encoded in the subfield is known to be not applicable (undefined, not relevant), then the subfield is valued by a string of "9s"; and when the information to be encoded is relevant but unknown (or missing), then the subfield is valued by a string of "9s."

Completeness_Report:

Certain node/geometry and topology (GT)-polygon/chain relationships are collected or generated to satisfy topological requirements. Some of these requirements include: chains must begin and end at nodes, chains must connect to each other at nodes, chains do not extend through nodes, left and right GT-polygons are defined for each chain element and are consistent throughout the transfer, and the chains representing the limits of the file (neatline) are free of gaps. The neatline is generated by connecting the four corners of the digital file, as established during initialization of the digital file. All data outside the enclosed region are ignored and all data crossing these geographically straight lines are clipped at the neatline. (Exception: During the QA/QC process all data is examined and if errors are found and corrections are possible, then data is corrected accordingly. This process is documented in the Process_Step.) Data within a specified tolerance of the neatline are snapped to the neatline. Neatline straightening aligns the digitized edges of the digital data with the generated neatline, that is, with the longitude/latitude lines in geographic coordinates. All internal polygons are tested for closure. Certain attributes and/or entities, e.g. closure line, convey data quality information. When information to be encoded in the subfield is known to be not applicable (undefined, not relevant), then the subfield is valued by a string of "9s"; and when the information to be encoded is relevant but unknown (or missing), then the subfield is valued by a string of "9s."

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: UNITED STATES GEOLOGICAL SURVEY

Publication_Date: 19840000

Title: Unavailable

Geospatial_Data_Presentation_Form: Map

Source_Scale_Denominator: 250000

Type_of_Source_Media: Map

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19720000

Ending_Date: 19840000

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: USGS

Source_Contribution:

Over the years, the USGS has collected digital elevation data using a number of production strategies including manual profiling from photogrammetric stereomodels; stereomodel digitizing of contours; digitizing topographic map contour plates; converting hypsographic and hydrographic tagged vector files; and performing autocorrelation via automated photogrammetric systems. Of these techniques, the derivation of DEM's from vector hypsographic and hydrographic data produces the most accurate model, and is the preferred method.

Process_Step:

Process_Description:

The process step describes, in general, the process used in the production of data sets. The originating agencies created the original spatial coverage. GeoPlan, during the QA/QC process included the following aspects: (1) Reprojected data to FGDL Albers (2) Set Precision to DOUBLE (3) Set Tolerances to FGDL Standards.

Process_Date: 20000000

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 8053

Column_Count: 8237

Vertical_Count: 1

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Albers Conical Equal Area

Albers_Conical_Equal_Area:

Standard_Parallel: 24.000000

Standard_Parallel: 31.500000

Longitude_of_Central_Meridian: -84.000000

Latitude_of_Projection_Origin: 24.000000

False_Easting: 400000.00000

False_Northing: 0.00000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Coordinate Pair

Coordinate_Representation:

Abscissa_Resolution: 90.0000

Ordinate_Resolution: 90.0000

Planar_Distance_Units: METERS

Geodetic_Model:

Horizontal_Datum_Name: D_North_American_1983_HARN

Ellipsoid_Name: GRS1980

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: USGSDEM.DBF

Entity_Type_Definition: Database File

Entity_Type_Definition_Source: None

Attribute:

Attribute_Label: VALUE

Attribute_Definition:

Floating point values that represent elevation relative to sea level.

Attribute_Definition_Source: Unknown

Attribute_Domain_Values:

Unrepresentable_Domain: Unknown

Attribute:

Attribute_Label: COUNT

Attribute_Definition: Count of occurances

Attribute_Definition_Source: Unknown

Attribute_Domain_Values:

Unrepresentable_Domain: Unknown

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Operator

Contact_Organization: FLORIDA GEOGRAPHIC DATA LIBRARY

Contact_Address:

Address_Type: Physical

Address:

431 Architecture Building PO Box 115706

City: Gainesville

State_or_Province: Florida

Postal_Code: 32611-5706

Contact_Voice_Telephone: (352) 3920997, Operator

Contact_Electronic_Mail_Address: <http://www.fgdl.org/fgdldocs/document/techsupp.htm>

Hours_of_Service: 24 Hours / Day

Contact_Instructions:

Please visit the web site, <http://www.fgdl.org>, for all questions or concerns.

Distribution_Liability:

Florida Geographic Data Library is a product of the University of Florida GeoPlan Center with support from the Florida Department of Transportation and the Florida Department of Environmental Protection. THE FGDL DATA AS PROVIDED BY CONTRIBUTING ORGANIZATIONS AND ANY PROGRAMMING SOFTWARE CREATED BY THE UNIVERSITY OF FLORIDA GEOPLAN CENTER (COLLECTIVELY THE "MATERIALS") ARE COPYRIGHTED BY THE UNIVERSITY OF FLORIDA GEOPLAN CENTER FOR THE FGDL CONTRIBUTING AGENCIES AND ORGANIZATIONS (THE "DATA PROVIDERS"). DO NOT REPRODUCE, REDISTRIBUTE OR RESELL THE MATERIALS, OR PROVIDE THE MATERIALS FOR FREE TO CUSTOMERS OR CLIENTS, OR PLACE THE MATERIALS FOR DOWNLOAD ON A WEBSITE. ADDITIONALLY, WHEN USING FGDL DATA OR SOFTWARE IN PROJECTS, MAPS, ETC.; YOU AGREE TO ACKNOWLEDGE THE FGDL AS A DATA SOURCE. THE MATERIALS ARE PROVIDED "AS IS". THE UNIVERSITY OF FLORIDA GEOPLAN CENTER MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE QUALITY OR SUITABILITY OF THE MATERIALS, EITHER EXPRESSLY OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE UNIVERSITY OF FLORIDA GEOPLAN CENTER MAKES NO WARRANTIES, GUARANTIES OR REPRESENTATIONS AS TO THE TRUTH, ACCURACY OR COMPLETENESS OF THE DATA PROVIDED BY THE FGDL CONTRIBUTING ORGANIZATIONS. THE UNIVERSITY OF FLORIDA GEOPLAN CENTER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED AS A RESULT OF USING, MODIFYING, CONTRIBUTING OR DISTRIBUTING THE MATERIALS.

Metadata_Reference_Information:

Metadata_Date: 20010000

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Operator

Contact_Address:

Address_Type: Physical

Address:

USGS Mapping Applications Center National Cartographic Info Center 507 National Center

City: Reston

State_or_Province: VA

Postal_Code: 22092

Contact_Voice_Telephone: (703) 860-6045

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998