This file is a modification of the eden dem released in October of 2007 (i.e., eden_em_oct07) in which the elevation values have been converted from meters (m) to centimeters(cm) for use by EDEN applications software. This file is intended specifically for use in the EDEN applications software. Aside from this difference in horizontal units, the following documentation applies.
Kevin Chartier John Jones, 200711, eden_dem_cm_nov07.nc.Online Links:
Planar coordinates are encoded using Row and Column
Abscissae (x-coordinates) are specified to the nearest 400
Ordinates (y-coordinates) are specified to the nearest 400
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.
The flattening of the ellipsoid used is 1/298.257.
954 577-6382 (voice)
kchart@ufl.edu
These data were specifically created for the development of water depth information using interpolated water surfaces from the EDEN stage data network.
Person who carried out this activity:
703 648-5543 (voice)
703 648-4165 (FAX)
jwjones@usgs.gov
Person who carried out this activity:
954 577-6382 (voice)
kchart@ufl.edu
Telis, Pamela, 2006, The Everglades Depth Estimation Network (EDEN) for support of ecological and biological assessments: USGS Fact Sheet 2006-3087, U.S. Geological Survey, St. Petersburg, FL.Online Links:
Jones, J. W., 2001, Image and in situ data integration to derive sawgrass density information for surface-flow modeling in the Everglades: International Association of Hydrological Sciences, Wallingford, Oxfordshire, UK.
Desmond, G. B., 2003, Measuring and mapping the topography of the Florida Everglades for Ecosystem Restoration: USGS Fact Sheet 021-03, U.S. Geological Survey, Reston, VA.Online Links:
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).
Source data (HAED) collected to better than +/- 15cm. Standard errors of cross-validation for the DEM range from ~7cm to 17cm depending on the EDEN subarea. This version is composed of new models created for WCA3N and the BCNP combined with the mosaic of two versions (i.e., eden_v002a for WCA1 and eden_v002c for all other EDEN subregions) that comprised EDEN_EM_JAN07. The previous mosaic was selected based on analysis of model performance in the water depth estimation process. The WCA1 surface was produced by removing all "upland" AHF points as defined by a reclassification of the Florida GAP process. For WCA1, the krigging model was developed based on statistics from the entire EDEN domain (the process for eden_v002a production). For each other EDEN sub-area (i.e., the other WCAs and the National Park) region specific krigging models were developed and applied.
Ground-surface elevation data were collected by the USGS at more than 50,000 points with an approximate spacing of 400 meters covering almost the entire Greater Everglades. The EDEN water-level network consists of hourly water-level data from 253 gaging stations (230 existing gaging stations and 23 new installations) and includes freshwater (nontidal) marsh gaging stations, boundary gages on canals, and coastal gaging stations operated by the Big Cypress National Preserve (BCNP), Everglades National Park (ENP), South Florida Water Management District (SFWMD), and USGS. The U.S. Army Corps of Engineers (USACE) and SFWMD recently documented or surveyed a majority of the hydrologic gages in the Greater Everglades to obtain correct values for converting water-level data from NGVD 29 to NAVD 88. The NAVD 88 datum is consistent in comparing water-level data across the Greater Everglades and computing accurate water depths.
The EDEN monitoring network includes ground-elevation measurements and continuous water-level data.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- These data were produced for EDEN operational water depth estimation and applications.
- Use_Constraints:
- The user is cautioned that this elevation model was produced specifically for EDEN applications and is based on input data of approximately 400m sample spacing and +/- 15cm vertical accuracy. No statement of appropriateness for uses other than that intended are implied.
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
hhenkel@usgs.gov
EDEN DEM in centimeters
The data have no explicit or implied guarantees.
Data format: | The file contains the elevations in centimeters in format netCDF (version CF-1.0) .zip Size: 0.462 |
---|---|
Network links: |
<http://sofia.usgs.gov/eden/data/dem/eden_dem_cm_nov07.nc> |
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
sofia-metadata@usgs.gov
U.S. Department of the Interior, U.S. Geological Survey
Comments and suggestions? Contact: Heather
Henkel - Webmaster
Generated by mp version 2.8.18 on Wed Nov 21 15:30:59 2007