By Peter Dartnell and James V. Gardner
U.S. Geological Survey Digital Data Series DDS-55
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director
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.
James V. Gardner
U.S. Geological Survey
Information Services, National Mapping Division
Denver Federal Center
Denver, CO 80225-0046
Telephone: (888) ASK-USGS
Current pricing information is available from http://mapping.usgs.gov/esic/prices/.