U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Cent, 2013, Estero Bay, California, NAD83 Bathymetry (Field Activity ID: S-05-12-SC): U.S. Geological Survey Open-File Report 2013-1225.Online Links:
This is a raster data set. It contains the following raster data types:
Planar coordinates are encoded using row and column
Abscissae (x-coordinates) are specified to the nearest 2.0
Ordinates (y-coordinates) are specified to the nearest 2.0
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983 (CORS96).
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.
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These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features. This information is not intended for navigational purposes.
This bathymetric data has not been independently verified for accuracy.
Uncertainty in the horizontal position of each sounding is a function of the total uncertainty propagated through each of the following component instruments: 1) vessel GPS, 2) intertial motion unit (IMU), 3) water sound velocity model, and 4) beam spreading in the water column. Assuming no systematic errors in the measurement instruments themselves, beam spreading is the dominate source of positional uncertainty. The 1.5-degree sonar beam of the SeaBat 7111 results in horizontal uncertainty ranging from 0.15 m at 10 m slant range, to about 0.70 m at 50 m slant range.
After filtering the data to remove obvious outliers, the standard deviation of the remaining sounding elevations was calculated for each 2 m x 2 m and 4 m x 4 m cell (each containing an average of 5 soundings for each 2 m cell, and 12 soundings for each 4 m cell) in CARIS. The mean standard deviation for all cells in the Elwha survey is 0.12 m, and 95 percent of the cells in the data set have a standard deviation of less than 0.30 m.
The 2012 mapping mission (U.S. Geological Survey (USGS) Field Activity ID: S-05-12-SC) collected high-resolution bathymetry and coregistered acoustic backscatter of outer Estero Bay, California. The survey was completed in 11 days, from July 30 to August 9, 2012, and consisted of 117 survey lines covering approximately 165 sq km in elevations ranging from about -45 m to -250 m relative to NAVD88. The survey extends from an existing bathymetric survey to approximately 15 km offshore with complete coverage within the area of interest.
All bathymetric values are derived from the same instruments and processing workflow.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- If physical samples or materials are available, constraints on their on-site access are described in "WR CMG Sample Distribution Policy" at URL: <http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html>
- Use_Constraints:
- This information is not intended for navigational purposes.
Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data.
Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.
This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
(831) 460-7814 (voice)
(831) 427-4748 (FAX)
shartwell@usgs.gov
Downloadable Data
This information is not intended for navigational purposes.
This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
| Data format: |
The ASCII file consists of header information containing a set of keywords, followed by cell values in row-major
order. The file format is:
<NCOLS xxx>
<NROWS xxx>
<XLLCENTER xxx | XLLCORNER xxx>
<YLLCENTER xxx | YLLCORNER xxx>
<CELLSIZE xxx>
{NODATA_VALUE xxx}
row 1
row 2
.
.
.
row n
where xxx is a number, and the keyword nodata_value is optional and defaults to -9999. Row 1 of the data is
at the top of the grid, row 2 is just under row 1 and so on. The nodata_value is the value in the ASCII file to be
assigned to those cells whose true value is unknown. In the grid they will be assigned the keyword NODATA.
Cell values are be delimited by spaces. No carriage returns are necessary at the end of each row in the grid
(although they are included in this case). The number of columns in the header is used to determine when a
new row begins. The number of cell values is equal to the number of rows times the number of columns.
in format ESRI ASCII Grid
(version 1.0)
Size: 700 MB
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| Network links: |
<http://pubs.usgs.gov/of/2013/1225/> |
(831) 460-7814 (voice)
shartwell@usgs.gov