Online Links:
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This data release makes the multibeam echosounder data from the 1998 survey of the sea floor offshore of Moriches Inlet, New York, available in digital form. The GeoTIFF image of shaded-relief bathymetry colored by backscatter intensity provides a visualization of both bathymetry and backscatter intensity. The shaded-relief image was created by vertically exaggerating the bathymetry 4 times and then artificially illuminating the relief by a light source positioned 45 degrees above the horizon from an azimuth of 60 degrees. The illumination from 60 degrees, approximately parallel to the survey lines, minimizes artifacts caused by small depth changes that may occur between lines. The backscatter intensity is represented by a suite of eight colors ranging from blue (low intensity) to green to yellow to red (high intensity).
1. Create a blank 8 bit map file:
Command line: make_blank mosaic_file
This command commences a dialog to enable an 8 bit image and input the map boundaries and resolution. The program also prompts for the projection type and parameters to be used creating the binary map file (custom Mercator projection, central longitude of -75 degrees, latitude of true scale 40 degrees north). Then the "blank" file is copied to two files required by the mosaic program:
Command line: cp mosaic_file.blank mosaic_file.mos
Command line: cp mosaic_file.blank mosaic_file.ran
2. Create backscatter files that can be then mosaicked from the backscatter time series:
Command line: getBeamPattern filename (prefix only)
Command line: makess -pixel 1.0 -beam_patt beampatt filename (prefix only) output.ss
Command line: glfill output.ss output.ss_fill (fills in data dropouts).
3. Mosaic all the backscatter files created in the last step (for each output.ss_fill), and then use a two-point linear contrast stretch (0-254; 255 is no data) to enhance the backscatter image.
Command line: mos2 -autoseam -maxazi 10 -maxdist 10 mosaic_file output.ss_fill
Command line: stretchacres -low 170 -high 210 -in mosaic_file -out mosaic_file.stretch
4. Create a shaded-relief image of the bathymetry using SwathEd routine addSUN (sun elevation of 45 degrees from 60, vertically exaggerating 4 times).
Command line: addSUN -elev 45 -azi 60 -vert_exag 4.0 gridFile.r4 filename.shade
5. Use a two-point linear contrast stretch (0-254; 255 is no data) to enhance the shaded-relief image:
Command line: stretchacres -low 150 -high 200 -in filename.shade -out filename_shade.stretch
6. Create an image of shaded-relief bathymetry, colored by backscatter intensity:
Command line: mix_ci -c mosaic_file.stretch -i filename_shade.stretch -m mosaic_file.pseudo Person who carried out this activity:
Command line: rawtopgm -headerskip 1024 image_width image_height mosaic_file.pseudo | pnmtoTIFF -none - > mosaic_pseudo.tif Person who carried out this activity:
Command line: jview mosaic_file.pseudo Person who carried out this activity:
Online Links:
Are there legal restrictions on access or use of the data?Access_Constraints: None
Use_Constraints: These data are not to be used for navigation purposes.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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 image of shaded-relief bathymetry colored by backscatter intensity at 3-m resolution and associated metadata from a multibeam survey offshore of Moriches Inlet, New York, compressed in a WinZip (version 14) file. in format GeoTIFF (version ArcGIS 9.3) GeoTIFF image Size: 2.6 |
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| Network links: |
https://www.sciencebase.gov/catalog/file/get/56ccd414e4b0b1892d9e0762?name=morich_srback3m.zip https://doi.org/10.5066/F7Z899GG |
The GeoTIFF image of shaded-relief bathymetry colored by backscatter intensity is compressed into a WinZip (version 14) file (morich_srback3m.zip). To use these data, the user must have software capable of uncompressing the zip file and ArcGIS or another GIS application package capable of viewing the data.