1_README.TXT


Sea-Floor Images and Data from Multibeam Surveys in
San Francisco Bay, Southern California, Hawaii, the 
Gulf of Mexico, and Lake Tahoe, California-Nevada


By
Peter Dartnell and James V. Gardner 


Digital Data Series DDS-55


1999


U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary


U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director


ISBN: 0-607-92491-8


For sale by U.S. Geological Survey, Information Services, 
National Mapping Division
Box 25046
Denver Federal Center
Denver CO.  80225-0046 
Telephone (888) ASK-USGS



QUICK START


Most computers with web browsers can read this CD-ROM, 
including, PC's running Windows 95 or higher, or Windows 
NT4.0 or higher, UNIX, and Macintosh. First, start the 
web browser and then open the "index.htm" file in the top 
directory of this CD-ROM.

INTRODUCTION 


Accurate base maps are a prerequisite for any geologic 
study, regardless of the objectives. Land-based studies 
commonly utilize aerial photographs, USGS 7.5-minute 
quadrangle maps, and satellite images as base maps. Until 
now, studies that involve the ocean floor have been at a 
disadvantage due to an almost complete lack of accurate 
marine base maps. Many base maps of the sea floor have been 
constructed over the past century but with a wide range in 
navigational and depth accuracies.

Only in the past few years has marine surveying technology 
advanced far enough to produce navigational accuracy of 1 
meter and depth resolutions of 50 centimeters. The Pacific 
Seafloor Mapping Project of the U.S. Geological SurveyÕs, 
Western Coastal and Marine Geology Program, Menlo Park, 
California, U.S.A., in cooperation with the Ocean Mapping 
Group, University of New Brunswick, Fredericton, Canada, 
is using this new technology to systematically map the 
ocean floor and lakes. This type of marine surveying, 
called multibeam surveying, collects high-resolution 
bathymetric and backscatter data that can be used for 
various base maps, GIS coverages, and scientific 
visualization methods.

This is an interactive CD-ROM that contains images, movies, 
and data of all the surveys the Pacific Seafloor Mapping 
Project has completed up to January 1999. The images and 
movies on this CD-ROM, such as shaded relief of the 
bathymetry, backscatter, oblique views, 3-D views, and 
QuickTime movies help the viewer to visualize the multibeam 
data. This CD-ROM also contains ARC/INFO export (.e00) files 
and full-resolution TIFF images of all the survey sites that 
can be downloaded and used in many GIS packages. 


DISCLAIMERS


This Compact Disc-Read Only Memory (CD-ROM) publication was 
prepared by an agency of the United States Government. 
Neither the United States Government nor any agency thereof, 
nor any of their employees, makes any warranty, expressed or 
implied, or assumes any legal liability or responsibility for 
the accuracy, completeness, or usefulness of any information, 
apparatus, product, or process disclosed in this report, or 
represents that its use would not infringe privately owned 
rights. Reference therein to any specific commercial product, 
process, or service by trade name, trademark, manufacturer, 
or otherwise does not necessarily constitute or imply its 
endorsement, recommendation, or favoring by the United States 
Government or any agency thereof.

Although all data and software published on this CD-ROM have 
been used by the USGS, no warranty, expressed or implied, is 
made by the USGS as to the accuracy of the data and related 
materials and (or) the functioning of the software. The act 
of distribution shall not constitute any such warranty, and 
no responsibility is assumed by the USGS in the use of this 
data, software, or related materials.


SYSTEM REQUIREMENTS

Compatible computers (all computers must have a CD-ROM 
     drive and capable of displaying at least 256 colors):

     -- UNIX

     -- Macintosh with a 68020 or higher processor (PowerPC 
          recommended)

     -- IBM-compatible computers running Windows 95 or higher      
          or NT4.0 or higher with a 386 or higher processor 
          (Pentium recommended).

Software:

     -- Most Web browsers

     -- ARC/INFO, or ARCVIEW with Spatial Analyst, or any GIS
          software that is capable of importing ARC/INFO      
          export (.e00) files.

     -- Any image-processing software capable of importing
          TIFF images.

This CD-ROM was produced in accordance with the ISO 9660 Level 2 
and Macintosh HFS standards. 


TO GET STARTED: 

Open the web browser on the computer. Under "Open File", open 
the "index.htm" file in the top directory of this CD-ROM. 
Navigate through the different survey areas by choosing the 
areas of your choice. View images of the ocean and lake 
floors by clicking on the various buttons. Load the Arc/Info 
export files, or TIFF images to your computer by clicking on 
the appropriate file name in the "Download Data" page.


FILES ON CD-ROM

1_README.TXT File
HTML files
GIF Images
QuickTime Movies
ARC/INFO Export files
metadata
TIFF Images
gzip decompression utility