## 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

U.S. Geological Survey Digital Data Series DDS-55Version 1.0

1999

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

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

[Pacific Sea Floor Mapping Logo]



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|IntroductionAccurate base maps are a prerequisite for any geological 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, U.S. GeologicalSurvey, Western Coastal and Marine Geology Program, Menlo Park, California,U.S.A. in cooperation with the Ocean Mapping Group, University of New Brunswick,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 bathymetry and backscatter data that can be used for a varietyof basemaps, 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. Images and movies on this CD-ROM, such as shaded reliefof the bathymetry, backscatter, oblique views, 3-D views, and Quicktimemovies (San Francisco, Los Angeles, and Lake Tahoe) 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 software. Click on the "Start Here" buttonabove to choose the survey location you are interested in.
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|               | CONTACTS         |                   
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|Project Chief: | James V. Gardner | jgardner@usgs.gov 
|GIS Manager:   | Peter Dartnell   | pdartnell@usgs.gov

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### Availability of this publication

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

ISBN:  0-607-92491-8

Current pricing information is available from http://mapping.usgs.gov/esic/prices/.

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