High Accuracy Elevation Data

Metadata:

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

Identification_Information:

Citation:

Citation_Information:

Originator: Greg Desmond

Publication_Date: 2003

Title: High Accuracy Elevation Data

Publication_Information:

Publication_Place: Reston, VA

Publisher: U.S. Geological Survey

Online_Linkage: <http://sofia.usgs.gov/projects/elev_data/>

Description:

Abstract:

The U.S. Geological Survey (USGS) is coordinating the aquisition of high accuracy elevation data. Three formats of the data are available for each data set: .cor files which contain complete lists of Global Positioning System point files, .asc files which are the same as the .cor files but have been reformatted to process into ARC/INFO coverages, and .e00 files which are the ARC/INFO coverages. The files are available in the same 7.5- by 7.5-minute coverages as USGS quadrangles. The elevation data is collected on a 400 by 400 meter grid. The elevations are referenced to the horizontal North American Datum of 1983 (NAD83) and vertical North American Vertical Datum of 1988 (NAVD88).

Purpose:

This project is performing regional topographic surveys to collect and provide elevation data to parameterize hydrologic and ecological numerical simulation models that are being developed for ecosystem restoration activities. Surveying services are also being rendered to provide vertical reference points for numerous water level gauges.

Modeling of sheet flow and water surface levels in the wetlands of South Florida is very sensitive to changes in elevation due to the expansive and extremely low relief terrain. Hydrologists have determined minimum vertical accuracy requirements for the elevation data for use as input to hydrologic models. As a result, elevation data with a vertical accuracy specification of +/-15 centimeters (cm) relative to the North American Vertical Datum of 1988 (NAVD88) are being collected in critical areas using state-of-the-art differential global positioning system (GPS) technology and data processing techniques.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1995

Ending_Date: Unknown

Currentness_Reference: ground condition

Status:

Progress: In Work

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -81.375

East_Bounding_Coordinate: -80.125

North_Bounding_Coordinate: 26.75

South_Bounding_Coordinate: 25.125

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: High accuracy elevation data

Theme_Keyword: mapping

Theme_Keyword: digital elevation data

Theme_Keyword: DEM

Theme_Keyword: elevation

Place:

Place_Keyword_Thesaurus:

Department of Commerce, 1995, Countries, Dependencies, Areas of Special Soverignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, D.C., National Institute of Standards and Technology

Place_Keyword: United States

Place_Keyword: US

Place:

Place_Keyword_Thesaurus:

U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, D. C., NIST

Place_Keyword: Florida

Place_Keyword: FL

Place:

Place_Keyword_Thesaurus:

Department of Commerce, 1990, Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas, FIPS 6-3, Washington, DC, National Institute of Standards and Technology

Place_Keyword: Broward County

Place_Keyword: Collier County

Place_Keyword: Miami-Dade County

Place_Keyword: Monroe County

Place:

Place_Keyword_Thesaurus: USGS Geographic Names Information System

Place_Keyword: Alligator Bay

Place_Keyword: Andytown

Place_Keyword: Big Boy Lake

Place_Keyword: Black Hammock

Place_Keyword: Big Lostmans Bay

Place_Keyword: Blackwater Sound

Place_Keyword: Chekika Island

Place_Keyword: Chokoloskee

Place_Keyword: Cooper City SW

Place_Keyword: Coopertown

Place_Keyword: Custard Apple Hammock

Place_Keyword: East of Lone Palm Head

Place_Keyword: Fifty Mile Bend

Place_Keyword: Flamingo

Place_Keyword: Forty Mile Bend

Place_Keyword: Gator Hook Swamp

Place_Keyword: Glades

Place_Keyword: Goulds

Place_Keyword: Grossman Hammock

Place_Keyword: Harney River

Place_Keyword: Hialeah SW

Place_Keyword: Homestead

Place_Keyword: Horseshoe Head

Place_Keyword: Indian Camp Creek

Place_Keyword: Joe Bay

Place_Keyword: Lake Ingraham East

Place_Keyword: Lake Ingraham West

Place_Keyword: Long Island

Place_Keyword: Long Pine Key

Place_Keyword: Lostmans River Ranger Station

Place_Keyword: Lostmans Trail

Place_Keyword: Madeira Bay

Place_Keyword: Mahogany Hammock

Place_Keyword: Melaleuka Head

Place_Keyword: Monroe Station

Place_Keyword: North of Forty Mile Bend

Place_Keyword: Ochopee

Place_Keyword: Pa-Hay-Okee Lookout Tower

Place_Keyword: Panther Mound

Place_Keyword: Pavillion Key

Place_Keyword: Pennsuco

Place_Keyword: Perrine

Place_Keyword: Royal Palm Ranger Station

Place_Keyword: Royal Palm Ranger Station SE

Place_Keyword: Shark Point

Place_Keyword: Shark River Island

Place_Keyword: Shark Valley Lookout Tower

Place_Keyword: South of Coopertown

Place_Keyword: South of Deem City

Place_Keyword: Tarpon Bay

Place_Keyword: Taylor Slough

Place_Keyword: West Lake

Place_Keyword: Whitewater Bay East

Place_Keyword: Whitewater Bay West

Place:

Place_Keyword_Thesaurus: none

Place_Keyword: Central Everglades

Place_Keyword: South East Coast

Place_Keyword: SW Big Cypress

Access_Constraints: none

Use_Constraints:

None. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Greg Desmond

Contact_Organization: U.S. Geological Survey

Contact_Position: Project Chief

Contact_Address:

Address_Type: mailing address

Address: 521 National Center

City: Reston

State_or_Province: VA

Postal_Code: 20192

Country: USA

Contact_Voice_Telephone: 703 648 4728

Contact_Facsimile_Telephone: 703 648 4165

Contact_Electronic_Mail_Address: gdesmond@usgs.gov

Hours_of_Service: 8:30-4:30 ET M-F

Browse_Graphic:

Browse_Graphic_File_Name: <http://sofia.usgs.gov/exchange/desmond/demplot.jpg>

Browse_Graphic_File_Description: Plot of DEM data produced at 30 meter grid spacing

Browse_Graphic_File_Type: JPEG

Data_Set_Credit:

GPS data converted to DEM's and ARC/INFO coverages by Vince Caruso. Data collection done by Charles Henkel, Gordon Shupe, Bob Glover, Ed Cyran, and Greg Desmond of the USGS and contractors.

Native_Data_Set_Environment:

.cor  comma delimited ASCII text file
.asc  ASCII text file reformatted to process into ARC/INFO coverage
.e00 ARC/INFO coverage

Data_Quality_Information:

Logical_Consistency_Report: not available

Completeness_Report:

The following data sets have missing files:

Goulds  missing .e00 file
Homestead  missing .cor file
Pennsuco  missing .cor file
Perrine  missing .asc file

The remianing data sets all have .asc, .cor, and .e00 files.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Horizontal positions are established by GPS observations and are referenced to the North American Datum of 1983 (NAD83). The desired horizontal accuracy is +/- 15 centimeters. This level of accuracy is consistent with GPS differential techniques which use two stations - a high-quality dual-frequency GPS receiver base station and a roving GPS station. The density and accuracy of a given GPS data observation varies from a few meters to a few centimeters according to the Position Dilution of Precision (PDOP) in the study area. Generally if the PDOP is observed to be excessive, data collection is discontinued or the data are discarded. The PDOP is an indicator of the positional accuracy of the GPS that be can derived from the current GPS satellite geometry, which varies continuously. Generally the smaller the PDOP number, the higher the data quality. The PDOP is a permanent part of the recorded data and is also included in the post processing procedures during reduction of the GPS observations to NAD 83. Where possible, the GPS base station has an ellipsoid height to an accuracy of two centimeters relative to the Continuously Operating Reference Stations (CORS) or the High Accuracy Reference Network (HARN), both operated by the National Geodetic Survey (NGS).

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

For all elevation data the vertical accuracy specification is +/- 15 centimeters and is referenced to NAVD 1988.

This elevation data is intended primarily for use in hydrological modeling. It is collected as high accuracy, "bare earth" ground elevation. That is, the data are restricted to ground elevations only. "Bare earth" in the Everglades swamp environment is generally considered to be the layer of "muck" which will support a one pound weight on a bearing surface of approximately 5.3 square inches (2.6 inch circle). In non-swamp areas it is actual bare ground.

Lineage:

Process_Step:

Process_Description:

The process consists of the following steps:

1. Collection of GPS XYZ points in and around the Everglades swamp and environs using the helicopter-based Airborne Height Finder (AHF) developed by the USGS. Additional elevation data were acquired through contracted professional surveying services.

2. The GPS data is processed into an ASCII list of coordinates in column order of Point number and/or descriptor attribute data (maximum of 20 characters), NAD83 geographic XY coordinates, and NAVD88 elevation Z value. This file is transformed through NADCON (a conversion program available from the National Geodetic Survey, NGS) to NAD83 UTM XY and NAVD88 Z coordinates. The file is output as an ASCII text file and transferred on-site Reston, VA to a file server/ mass storage device.

3. The coordinates are then processed into an ARC INFO POINT COVER format. An annotation file is created and appended to the POINT cover file for the tabular elevation value of meters to the decimal value of 100th of meter (centimeter). This annotation value is later used to create the illustrated large area point plot file in GEO TIFF format.

4. The POINT cover is then transformed to other final distribution formats.

a. The POINT cover is exported into ARC/INFO Exchange Format (.e00) and transferred to a file server/mass storage device.

b. The POINT cover is used as input to ARC TOPOGRID to create the ARC GRID elevation file.

c. The ARC GRID cover is then used as input to ARC GRIDPAINT in combination with a color ramp and color map file to create the illustrated pseudo-color elevation plot.

Process_Date: Unknown

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Vince Caruso

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing address

Address: 521 National Center

City: Reston

State_or_Province: VA

Postal_Code: 20192

Country: USA

Contact_Voice_Telephone: 703 648 4586

Contact_Facsimile_Telephone: 703 648 4614

Contact_Electronic_Mail_Address: vcaruso@usgs.gov

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference: South Florida - Everglades

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: Universal Transverse Mercator

Universal_Transverse_Mercator:

UTM_Zone_Number: 17

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.9996

Longitude_of_Central_Meridian: -81

Latitude_of_Projection_Origin: 0

False_Easting: 500000

False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Coordinate Pair

Coordinate_Representation:

Abscissa_Resolution: 400

Ordinate_Resolution: 400

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298.257

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: North American Vertical Datum of 1988

Altitude_Resolution: .01

Altitude_Distance_Units: meters

Altitude_Encoding_Method:

Explicit elevation coordinate included with horizontal coordinates

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Roy Sonenshein

Contact_Organization: U.S. Geological Survey

Contact_Position: Database Manager

Contact_Address:

Address_Type: mailing address

Address:

9100 NW 36th Street

Suite 107

City: Miami

State_or_Province: FL

Postal_Code: 33178

Country: USA

Contact_Voice_Telephone: 305 717-5824

Contact_Facsimile_Telephone: 305 717-5801

Contact_Electronic_Mail_Address: sunshine@usgs.gov

Resource_Description: High accuracy elevation data

Distribution_Liability: No warrantees are implied or explicit for the data

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: ARCE

Format_Version_Number: 7.0

Format_Specification: .e00

Format_Information_Content:

export-formatted interchange file in ASCII for input into ARC/INFO and ArcView

Transfer_Size: 1

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://sofia.usgs.gov/exchange/desmond/desmondelev.html>

Access_Instructions: Log onto <http://sofia.usgs.gov>

Digital_Form:

Digital_Transfer_Information:

Format_Name: ASCII

Format_Version_Date: 1985

Format_Specification: .asc

Format_Information_Content:

comma delimited complete list of Global Positioning System (GPS) points

Transfer_Size: 0.1

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://sofia.usgs.gov/exchange/desmond/desmondelev.html>

Access_Instructions: Log onto <http://sofia.usgs.gov>

Digital_Form:

Digital_Transfer_Information:

Format_Name: ASCII

Format_Version_Date: 1985

Format_Specification: .cor

Format_Information_Content:

complete list of GPS points reformatted to process into ARC/INFO

Transfer_Size: 0.2

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://sofia.usgs.gov/exchange/desmond/desmondelev.html>

Access_Instructions: Log onto <http://sofia.usgs.gov>

Fees: none

Metadata_Reference_Information:

Metadata_Date: 20031210

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Jo Anne Stapleton

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing address

Address: 521 National Center

City: Reston

State_or_Province: VA

Postal_Code: 20192

Country: USA

Contact_Voice_Telephone: 703 648-4592

Contact_Facsimile_Telephone: 703 648-4614

Contact_Electronic_Mail_Address: jastapleton@usgs.gov

Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology
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Generated by mp version 2.8.5 on Wed Dec 10 12:01:55 2003