Download Data

Arc/Info Export Files

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

1. Bathymetry - Depth


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


Full Resolution TIFF Images

There are three full resolution TIFF images availablefor Maui 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. mi_shd.tif.gz: Shaded relief of bathymetry using a multi-directionalhillshading AML **

2. mi_bathy.tif.gz : Bathymetry

3. mi_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 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 the central Hawaiian Islands between Maui,Molokai, Lania, and Kahoolawe was done between February 9 and February 22,1998, using a Kongsberg Simrad EM-300 Multibeam System hull mounted to C&CTechnologies' RV Ocean Alert. For more information, refer to USGS, OpenFile 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


 Cell Size =20.000
 Data Type: Floating Point
 Number of Rows= 4139
 Number of Columns = 3562
 Xmin = 720885.875
 Xmax = 792125.875
 Ymin = 2271179.750
 Ymax = 2353959.750
 Minimum Value = -711.470
 Maximum Value =-22.451
 Mean = -287.512
 Standard Deviation = 174.998
 Projection UTM
 Zone 4
 Datum WGS84
 Spheroid WGS84


 Cell Size = 20.000
 Data Type: Floating Point
 Number of Rows= 2641
 Number of Columns = 3145
 Xmin = 590043.875
 Xmax = 652943.875
 Ymin = 2339233.000
 Ymax = 2392053.000
 Minimum Value =88.684
 Maximum Value =249.000
 Mean =174.276
 Standard Deviation = 13.455
 Projection UTM
 Zone 4
 Datum WGS84
 Spheroid WGS84

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