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 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme_Keyword: imageryBaseMapsEarthCover Theme_Keyword: 006 Theme_Keyword: 010 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_Keyword: Big Lake Place_Keyword: West of Big Lake Place_Keyword: Coral Springs NE Place_Keyword: Fifty Mile Bend Place_Keyword: Gator Lake Place_Keyword: Greenacres City Place_Keyword: Lone Palm Head Place_Keyword: Loxahatchee Place_Keyword: Loxahatchee NW Place_Keyword: Loxahatchee SE Place_Keyword: Loxahatchee SW Place_Keyword: University Park Place_Keyword: West of Pennsuco 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 Browse_Graphic: Browse_Graphic_File_Name: http://sofia.usgs.gov/exchange/desmond/statusmap-big.jpg Browse_Graphic_File_Description: status map for elevation data 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: 20041027 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