U.S. Geological Survey, 2007, APBAYHS_GEOG.TIF - Hillshaded GeoTIFF image of the Bathymetry of Apalachicola Bay and St. George Sound, FL: Open-File Report 2006-1381, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.This is part of the following larger work.Online Links:
Twichell, David C. , Andrews, Brian D. , Edmiston, H. Lee , and Stevenson, William R. , 2007, Geophysical Mapping of oyster habitats in a shallow estuary; Apalachicola Bay, Florida: Open-File Report 2006-1381, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.Online Links:
This is a Raster data set. It contains the following raster data types:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
The purpose of this dataset is to provide a bathymetric hillshade GeoTIFF image in a geographic projection from swath bathymetry collected within the survey boundary in St. George Sound and Apalachicola Bay.
U.S. Geological Survey, 2007, APBAYBATH25M - 25m Bathymetric ArcRaster Grid of Apalachicola Bay and St. George Sound, Florida: Open-File Report 2006-1381, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.This is part of the following larger work.Online Links:
Twichell, David C. , Andrews, Brian D. , Edmiston, H. Lee , and Stevenson, William R. , 2007, Geophysical Mapping of oyster habitats in a shallow estuary; Apalachicola Bay, Florida.Online Links:
Person who carried out this activity:
508-548-8700 x 2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
508-548-8700 x 2266 (voice)
508-457-2310 (FAX)
dtwichell@usgs.gov
Data sources produced in this process:
Person who carried out this activity:
508-548-8700 x 2266 (voice)
508-457-2310 (FAX)
dtwichell@usgs.gov
Data sources produced in this process:
DGPS is assumed to be accurate within 1-2 meters. Standard GPS is assumed accurate within 5-10 meters. 99% of the positional data is DGPS. Unless noted, all GPS/DGPS data is referenced to WGS84 (NAD83). The configuration of the fathometer is as follows: The fathometer is mounted on a pole at the bow of the R/V RAFAEL. Offset between the fathometer pole and GPS antenna is measured. On ASV IRIS, the seismic profiler from which single-beam bathymetry measurements were collected was directly below the GPS antenna. No measurements were taken of ship's pitch, yaw, heave, or change in draft due to water and fuel usage. Motion of the fathometer is not measured. Horizontal accuracy of the fathometer is assumed to be within +/- 3 meters.
Ship motion was recorded with a TSS DMS 2-05 Attitude Sensor, mounted on a head above the interferometric Submetrix 2000 Series transducers. Navigation was recorded using Real Time Kinematic Differential Global Positioning System (RTK-DGPS). The interferometric sonar is an angle-measuring system; depth accuracy decreases with increasing horizontal range. The combined angular accuracy of the Submetrix 2000 Series and the TSS DMS 2-05 attitude sensor is documented as 0.1 degrees. Assuming a constant angular accuracy, and using the International Hydrographic Standard (IHO) of a required 0.3 meter accuracy in < 30 meter water depth, all data collected within the survey fall within the IHO accuracy standards. However, vertical accuracy is also directly affected by the accuracy of both the navigation system and tidal measurements. RTK DGPS vertical accuracy is assumed to be 0.2 meters. Tidal elevations were derived from RTK -DGPS heights sent from a survey-specific base station located on St. George Island.
The base station occupied a temporary monument. The x & y positions were calculated for that location using a 3 day average of 12 hour data sets using the Online Positioning User Service (OPUS, National Geodetic Survey) solution. Tidal elevations were calculated from NOAA Tidal Station #8728690 using the same OPUS solution and then applied to the corrected elevations for the base station at St. George Island. Antenna heights were referenced to Mean Lower Low Water (MLLW) for easier comparison of NOAA nautical charts
Pockmark features that appear in the dredge channel of the intracoastal waterway fairways are artifacts of the processing methods used to generate a continuous surface from swath bathymetry collected on lines spaced 100m apart.
These data have not been quantitatively compared to previous hydrographic data, although they generally agree with qualitative comparison of published NOAA charts.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Data are not intended for navigational use.
These data should not be used at resolutions for which it is not intended.
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
Downloadable Data
Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
| Data format: | GeoTIFF hillshade image of the bathymetric data collected in the Apalachicola Bay and St. George Sound Florida in format TIFF (version ArcGIS 9.2) GeoTIFF Size: 0.000 |
|---|---|
| Network links: |
<http://pubs.usgs.gov/of/2006/1381/GIS/raster/bath/apbayhs_geog.zip> |
| Media you can order: |
DVD-ROM
(Density 4.75
Gbytes)
(format UDF)
Note: None
|
These data are available in GeoTIFF format. The user must have software capable of viewing a GeoTIFF data file.
508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
