USGS Geologic Division Coastal and Marine Geology Program GOMAINE

Construction of Digital Bathymetry for the Gulf of Maine

DATA PRODUCTS

Images

Colored sun-illuminated images of the topography were created in GMT by Mercator projecting the geographic grids and using the grdgradient and grdimage routines to generate a PostScript image. The resulting PostScript files were converted to TIFF files for use in paint and draw packages and display on the Web.

gom15a.tiff -- (5.5mb) 15 second Grid 1584 x 1646
gom15a.jpg --(571 kb) 15 second Grid 1584 x 1646
gom30a.tiff -- (2.1 mb) 30 second Grid 1008 x 1048
gom30a.jpg-- (239 kb) 30 second Grid 1008 x 1048
gom30b.tiff -- (559 kb) 30 second Grid 504 X 524
gom30b.jpg -- (42 kb) 30 second Grid 504 X 524

 

The GMT produced 15 and 30 second grids were also exported as XYZ ASCII files and then read into Arc using the ASCII2GRID command to produce Arc grid files. Contours were then generated in ARC using the LatticeContour command.

Click for high-res image

The image above consists of the 15 arc-second grid, contours
generated in ArcInfo, and the WVS shoreline:

Grids and Contours

Grids
The 15 and 30 second grids in Arc, GMT, Matlab and ASCII XYZ formats.

ArcInfo
gom15dd.e00.gz -- (10.2 mb) The 15 arc-second ArcInfo format grid.
gom30dd.e00.gz -- ( 2.6 mb) The 30 arc-second ArcInfo format grid. 

GMT binary NETCDF files
gom15.grd.gz -- (11.4 mb) 15 arc second grid
gom30.grd.gz -- (2.9 mb) 30 arc second grid

Matlab
The GMT grids were read into Matlab and exported as Matlab binary .mat files.
gom15.mat.gz --(12.8 mb)
gom30.mat.gz --(3.3 mb)

Ascii XYZ
gom_15.xyz.gz -- (19.9 mb) ASCII xyz file containing the 15 arc second grid.
gom_30.xyz.gz -- ( 5.1 mb) ASCII xyz file containing the 15 arc second grid.


Contours
Contours lines were generated at the following intervals from the 15 second grid:
{-4000.000, -3000, -2000, -1000, -500, -400, -300, -280, -260, -240, -220, -200, -180, -160,-140, -120, -100, -90, -80, -70, -60, -50, -40, -30, -20, -15, -10, -5}


ArcInfo
Contours in Arc's Export .e00 format:
selcontdd.e00.gz -- (14.6 mb)

Matlab (or other applications)
contasc.tar.gz -- (7 Mb)   Tar file containing 28 ASCII files suitable for reading into Matlab or other programs. Arc segments delimited by nan nan.

contasc2.tar.gz -- (3.5 Mb) Same as contasc.tar.gz, but bathy lines from the 15 second grid were decimated using a coastline reduction algorithm such that only 1/2 the number of points remained.

contasc4.tar.gz -- (1.5 Mb)   Same as contasc.tar.gz, but bathy lines from the 15 second grid were decimated using a coastline reduction algorithm such that only 1/4 the number of points remained.

contasc8.tar.gz -- (0.7 Mb)   Same as contasc.tar.gz, but bathy lines from the 15 second grid were decimated using a coastline reduction algorithm such that only 1/8 the number of points remained.

contasc16.tar.gz -- (0.4 Mb)   Same as contasc.tar.gz, but bathy lines from the 15 second grid were decimated using a coastline reduction algorithm such that only 1/16 the number of points remained.   This still looks pretty good for most applications.  You might try this first!

 

 

Processed Sounding and Elevation Data

The following files are ASCII formatted files that have been gzipped to save space.   In all of the following files, there are three columns containing longitude (west negative), latitude (north positive) and topographic elevation in meters above mean sea level.  Thus water depths are negative and land elevations are positive.    The horizontal datum is NAD83 and the vertical datum is MSL.

Click for High-res image  

noshdb.xyz.gz --(23 mb) National Ocean Service Hydrographic Survey Data from NGDC.

 

Click for High-res image lssale52.xyz.gz --(469 kb) Marine Trackline Bathymetric Data from NGDC.

 

Click for High-res image greenberg.xyz.gz -- (135 kb) Bathymetry data retrieved online from the U.S. GLOBEC Georges Bank Program web site, originally generated by  David Greenberg from the Bedford Institute of Oceanography.

 

Click for High-res image c_flagg.xyz.gz -- (179 kb) Bathymetry data retrieved online from the U.S. GLOBEC Georges Bank Program web site, provided by Charlie Flagg. This is shiptrack bathymetry data from acoustic doppler current profiler cruisse to Georges Bank. Uncorrected for tides so values are probally good +- 1.5 meters.

 

Click for High-res image offshore.xyz.gz --(10 kb) ETOPO5 5 minute bathymetry from the Defense Mapping Agency and  the 2000 and 3000 meter isobaths from the GEBCO General Bathymetric Chart of the Oceans from International Hydrographic Office.

 

Click for High-res image dbdbv.xyz.gz -- (2.4 mb) Bathymetric data from the DBDB-V Digital Bathymetry Data Base from the Naval Oceanographic Office.
NOAA Medium Resolution Digital Shoreline and DMA World Vector Shoreline
ArcInfo
wvsdd.e00.gz -- (495 kb) DMA World Vector Shoreline
ec80_coast.e00.gz --(1.3 mb) NOAA Medium resolution digital Shoreline
ASCII xyz
wvs_coast.xyz.gz -- (152 kb) DMA World Vector Shoreline
ec80_coast.xyz.gz -- (975 kb) NOAA Medium resolution digital Shoreline



For comments and questions, contact Rich Signell

 

 

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