Download Data



Arc/Info Export Files

There are two ARC/INFO export files (.e00) availablefor the Kauai survey on this CD-ROM;

1. Bathymetry - Depth

ki_bathy.e00.gz

2. Backscatter - Digital number (DN) associated with the reflected energyoff the seafloor

ki_back.e00.gz


Full Resolution TIFF Images

There are three full resolution TIFF images availablefor Kauai on this CD-ROM.

These files can be added to a GIS system by creatinga world file using the information from the Arc/Info Grid Information below.

Or these files can be directly opened in many imageprocessing programs such as Adobe Photoshop and Adobe Illustrator.

1. ki_shd.tif.gz: Shaded relief of bathymetry using a multi-directionalhillshading AML **

2. ki_bathy.tif.gz : Bathymetry

3. ki_back.tif.gz: Backscatter

** Multi-directionalhillshading AML created by Florence Wong, U.S. Geological Survey, MenloPark CA.


Formal Metadata


Download Instructions

1. Download compressed ARC/INFO export and TIFFfiles into drive and/or folder.

2. Uncompress files using decompression program.There are different decompressing programs for specific computer platforms.

 - UNIX usually has a version of GZIP alreadyunstalled on the system. If not, there are four of the more common GZIPprograms on this CD-ROM (Alpha Dec, SGI, Sparc-Solaris 2.5 and 2.6). Thesecan be found in the top directory of this CD-ROM in the GZIP folder underUNIX. If you are on a different system go to www.gzip.org to findthe GZIP program that will work for you.

- Window users may use Winzip to decompressthese files. There is also a freeware Windows version of GZIP on this CD-ROM.This can be found in the top directory of this CD-ROM in the GZIP folderunder Windows.

-Macintosh users may use MacGZIP. There is a copy on this CD-ROM. Thiscan be found in the top directory of this CD-ROM in the GZIP folder underMac.

3 "Import" the Arc/Info export filesusing the grid option.


Data Collection

Mapping offshore Kauai was done between February4 and February 6, 1998 using a Kongsberg Simrad EM-300 Multibeam Systemhull mounted to C&C Technologies' RV Ocean Alert. For more information,refer to USGS, Open File Report 98-212.


Processing Steps

1. Bathymetry and backscatter data processed onSilicon Graphic computer using software developed by the Ocean Mapping Group,University of New Brunswick. (see USGSOpen File Report 98-509, The Bathymetry of Lake Tahoe, California-Nevada)
2. Processed data downloaded to a Sun Sparc Ultra 2, running Solaris 2.5as an ascii file (longitude, latitude, depth, or backscatter DN value)
3. In Arc/Info 7.1.2 a point coverage is created from the ascii file.
4. Point coverge is projected from Geographic Coordinate System to UTM projection.
5. Projected point coverage is gridded using IDW (Inverse Distance Weighted)function.
6a. Grid is exported to Arc/Info export (.e00) file.
6b. Grid is converted to a TIFF image using the "Gridimage" command.
7. Both the export and TIFF files are compressed using UNIX version of GZIP.


Arc/Info Grid Information

Bathymetry

 Cell Size =20.000
 Data Type: Floating Point
 Number of Rows= 1362
 Number of Columns = 2565
  
 BOUNDARY 
 Xmin = 430855.375
 Xmax = 482155.375
 Ymin = 2403231.500
 Ymax = 2430471.500
  
 STATISTICS 
 Minimum Value = -3117.521
 Maximum Value =-33.010
 Mean = -1659.188
 Standard Deviation = 754.890
  
COORDINATE SYSTEM DESCRIPTION 
 Projection UTM
 Zone 4
 Datum WGS84
 Units METERS
 Spheroid WGS84

Backscatter

 Cell Size = 20.000
 Data Type: Floating Point
 Number of Rows= 1362
 Number of Columns = 2565
  
 BOUNDARY 
 Xmin = 430855.375
 Xmax = 482155.375
 Ymin = 2403231.500
 Ymax = 2430471.500
  
 STATISTICS 
 Minimum Value = 6.000
 Maximum Value =247.317
 Mean =183.011
 Standard Deviation = 11.305
  
COORDINATE SYSTEM DESCRIPTION 
 Projection UTM
 Zone 4
 Datum WGS84
 Units METERS
 Spheroid WGS84



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