Identification_Information: Citation: Citation_Information: Originator: Greg Desmond Publication_Date: 2007 Title: High Accuracy Elevation Data - Lake Okeechobee Littoral Zone Geospatial_Data_Presentation_Form: text files, shapefile Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: http://sofia.usgs.gov/exchange/desmond/desmondelev.html Description: Abstract: The U.S. Geological Survey (USGS) coordinated the acquisition of high accuracy elevation data (meters) for the Lake Okeechobee Littoral Zone collected on a 400 meter topographic grid with a vertical accuracy of +/- 15 centimeters. The elevations are referenced to the horizontal North American Datum of 1983 (NAD83) and vertical North American Vertical Datum of 1988 (NAVD88). The topographic surveys were performed using differential GPS technology and a USGS developed helicopter-based instrument known as the Airborne Height Finder (AHF). The data are available for the areas shown on the USGS High Accuracy Elevation Data graphic at http://sofia.usgs.gov/exchange/desmond/desmondelev.html. Purpose: This project performed 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. 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: 20060724 Ending_Date: 20061012 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -81.25 East_Bounding_Coordinate: -80.625 North_Bounding_Coordinate: 27.25 South_Bounding_Coordinate: 26.625 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: 006 Place: Place_Keyword_Thesaurus: Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, DC, 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, DC, 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: Okeechobee County Place_Keyword: Palm Beach County Place_Keyword: Hendry County Place_Keyword: Glades County Place: Place_Keyword_Thesaurus: USGS Geographic Names Information System Place_Keyword: Belle Glade Place_Keyword: Cochrans Pass Place_Keyword: Fisheating Bay Place_Keyword: Lakeport Place_Keyword: Lake Harbor Place_Keyword: Moore Haven Place_Keyword: Okeechobee Place_Keyword: Pahokee Place_Keyword: Lake Okeechobee Place: Place_Keyword_Thesaurus: none Place_Keyword: Lake Okeechobee Littoral Zone Place_Keyword: Greater Lake Okeechobee Place_Keyword: Brighton SE Place_Keyword: Clewiston North Place_Keyword: Clewiston South Place_Keyword: Loxahatchee NW Place_Keyword: Loxahatchee SE Place_Keyword: Loxahatchee SW 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: Bob Glover 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: 703 648-5056 Contact_Electronic_Mail_Address: rglover@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://sofia.usgs.gov/exchange/desmond/atlas/ Browse_Graphic_File_Description: map of USGS topographic quads containing elevation data around Lake Okeechobee Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://sofia.usgs.gov/exchange/desmond/desmondelev.html Browse_Graphic_File_Description: map showing the location of high accuracy elevation data around Lake Okeechobee Browse_Graphic_File_Type: GIF Data_Set_Credit: GPS data converted to ESRI shapefile by Susan D. Price. Data collection done by Charles Henkle and Ed Cyran as USGS contractors. Native_Data_Set_Environment: comma-separated values file and ESRI shapefile Data_Quality_Information: Logical_Consistency_Report: not available Completeness_Report: All verified and accepted data points are included in the files for each area 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 and vegetation classification in the Lake Okeechobee Littoral Zone using the helicopter-based Airborne Height Finder (AHF) developed by the USGS. 2. The GPS data were processed into an ASCII list of NAD83 geographic XY coordinates, NAVD88 elevation Z value and descriptor attribute data. This file was transformed using Corpscon, version 5.11.08 from the U.S. Army Corps of Engineers to NAD83 UTM XY and NAVD88 Z coordinates. The file was output as an ASCII text file and processed at USGS in Reston, VA. 3. The x,y, and z values of the ASCII text file were reformatted to the decimal value of 100th of meter (centimeter) to represent the accuracy of the data and then imported into ArcGIS 9.1 to create an ESRI shapefile. 4. The ESRI shapefile was compressed into a .zip file using WinZip. The associated .dbf files were opened in MS Excel and saved as the comma separated value file which also is available for download. Process_Date: 200708 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Susan D. Price 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 6692 Contact_Electronic_Mail_Address: sprice@usgs.gov Spatial_Data_Organization_Information: Indirect_Spatial_Reference: South Florida - Lake Okeechobee Littoral Zone Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 2865 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 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: ELEV_M Entity_Type_Definition: ground surface elevation in meters Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: X_UTM Entity_Type_Definition: UTM X coordinate in meters for the data collection point Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: Y_UTM Entity_Type_Definition: UTM Y coordinate in meters for the data collection point Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: QUAD_NAME Entity_Type_Definition: The name of the USGS 1:24,000-scale topographic quadrangle in which the point falls Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: VEG_FS Entity_Type_Definition: The vegetation observed by the surveyor at the data collection point. Vegetation types include Alligator Hole, Broadleaf Emergent, Cattail, Cypress, Floating Emergent, Hardwood, Lygodium, Melaleuca, Open Water, Palmetto, Pine, Sawgrass, Shrub, Slough, Tree Island, Wet Prairie, Wet Prairie/Slough, and Willow Shrub Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: SUR_METHOD Entity_Type_Definition: type of surveying method - all data for the Lake Littoral zone were collected using the helicopter based Airborne Height Finder (AHF) Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: SUR_INFO Entity_Type_Definition: Characters 1-5 are the file name used by the surveyor during data collection. Characters 6-8 are the Julian date of the data collection. Characters 9-10 are the year the data were collected. Character 11 is a blank space. Characters 12-19 represent the date the data were released for publication and archive after the data have been collected, processed, edited, quality controlled, and approved for release. Character 20 is "Y" which means the data can be released. This is not the date the data were collected. If new data were added to the quadrangle, the revision date was modified for ALL points in the quadrangle to reflect the latest revision date. At the completion of data collection, the individual quad-based files were aggregated to create the larger files now available for download. Entity_Type_Definition_Source: USGS Detailed_Description: Entity_Type: Entity_Type_Label: SUR_FILE Entity_Type_Definition: file name used by the surveyor for internal data management purposes Entity_Type_Definition_Source: USGS Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Heather S.Henkel Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: 600 Fourth St. South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 803-8747 ext 3028 Contact_Facsimile_Telephone: 727 803-2030 Contact_Electronic_Mail_Address: hhenkel@usgs.gov Resource_Description: Helicopter - Airborne Height Finder Distribution_Liability: No warrantees are implied or explicit for the data Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ASCII Format_Version_Date: 1985 Format_Specification: .csv Format_Information_Content: comma separated values file of Global Positioning System (GPS) points Transfer_Size: 0.261 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://sofia.usgs.gov/exchange/desmond/desmondelev.html Access_Instructions: File may be downloaded from the SOFIA website Digital_Form: Digital_Transfer_Information: Format_Name: zip Format_Version_Number: unknown Format_Specification: shp.zip Format_Information_Content: ArcGIS shapefile and associated files File_Decompression_Technique: the file must be unzipped before use Transfer_Size: 0.109 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://sofia.usgs.gov/exchange/desmond/desmondelev.html Access_Instructions: File may be downloaded from the SOFIA website Fees: none Metadata_Reference_Information: Metadata_Date: 20071024 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Heather Henkel Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 600 Fourth Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727 803-8747 ext 3028 Contact_Facsimile_Telephone: 727 803-2030 Contact_Electronic_Mail_Address: sofia-metadata@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998