Greg Desmond 2007 text files, shapefile Reston, VA U.S. Geological Survey http://sofia.usgs.gov/exchange/desmond/desmondelev.html 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. 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. 20060724 20061012 ground condition Complete As needed -81.25 -80.625 27.25 26.625 none High accuracy elevation data mapping digital elevation data DEM elevation ISO 19115 Topic Category elevation 006 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 United States US 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 Florida FL 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 Okeechobee County Palm Beach County Hendry County Glades County USGS Geographic Names Information System Belle Glade Cochrans Pass Fisheating Bay Lakeport Lake Harbor Moore Haven Okeechobee Pahokee Lake Okeechobee none Lake Okeechobee Littoral Zone Greater Lake Okeechobee Brighton SE Clewiston North Clewiston South Loxahatchee NW Loxahatchee SE Loxahatchee SW none None. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Bob Glover U.S. Geological Survey mailing address

521 National Center

Reston VA 20192 USA 703 648-5056 rglover@usgs.gov http://sofia.usgs.gov/exchange/desmond/atlas/ map of USGS topographic quads containing elevation data around Lake Okeechobee GIF http://sofia.usgs.gov/exchange/desmond/desmondelev.html map showing the location of high accuracy elevation data around Lake Okeechobee GIF GPS data converted to ESRI shapefile by Susan D. Price. Data collection done by Charles Henkle and Ed Cyran as USGS contractors. comma-separated values file and ESRI shapefile not available All verified and accepted data points are included in the files for each area 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). 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. 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. 200708 Susan D. Price U.S. Geological Survey mailing address

521 National Center

Reston VA 20192 USA 703 648 6692 sprice@usgs.gov South Florida - Lake Okeechobee Littoral Zone Vector Entity point 2865 Universal Transverse Mercator 17 0.9996 -81 0 500000 0 Coordinate Pair 400 400 meters North American Datum of 1983 Geodetic Reference System 80 6378137 298.257 North American Vertical Datum of 1988 .01 meters Explicit elevation coordinate included with horizontal coordinates ELEV_M ground surface elevation in meters USGS X_UTM UTM X coordinate in meters for the data collection point USGS Y_UTM UTM Y coordinate in meters for the data collection point USGS QUAD_NAME The name of the USGS 1:24,000-scale topographic quadrangle in which the point falls USGS VEG_FS 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 USGS SUR_METHOD type of surveying method - all data for the Lake Littoral zone were collected using the helicopter based Airborne Height Finder (AHF) USGS SUR_INFO 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. USGS SUR_FILE file name used by the surveyor for internal data management purposes USGS Heather S.Henkel U.S. Geological Survey mailing address

600 Fourth St. South

St. Petersburg FL 33701 USA 727 803-8747 ext 3028 727 803-2030 hhenkel@usgs.gov Helicopter - Airborne Height Finder No warrantees are implied or explicit for the data ASCII 1985 .csv comma separated values file of Global Positioning System (GPS) points 0.261 http://sofia.usgs.gov/exchange/desmond/desmondelev.html File may be downloaded from the SOFIA website zip unknown shp.zip ArcGIS shapefile and associated files the file must be unzipped before use 0.109 http://sofia.usgs.gov/exchange/desmond/desmondelev.html File may be downloaded from the SOFIA website none 20071024 Heather Henkel U.S. Geological Survey mailing and physical address

600 Fourth Street South

St. Petersburg FL 33701 USA 727 803-8747 ext 3028 727 803-2030 sofia-metadata@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998