The Gulf of the Farallones National Marine Sanctuary: Sidescan-Sonar Imagery Open-File Report 2004-1082 By Sweeney, E.M.¹, Danforth, W.W.¹, Karl, H.A.², O'Brien, T.F.¹, Schwab, W.C.¹ ¹U.S. Geological Survey, Woods Hole, MA ²U.S. Geological Survey, Menlo Park, CA Table of Contents: Introduction CD Directory Structure Getting Started System Requirements Disclaimer Introduction In 1989, the U.S. Geological Survey (USGS) began a major geologic and oceanographic investigation of the Gulf of the Farallones continental shelf system, designed to evaluate and monitor human impacts on the marine environment (Karl and others, 2002). The study region is located off the central California coast, adjacent to San Francisco Bay and encompasses the Gulf of Farallones National Marine Sanctuary. Geologic mapping of this area included the use of various remote sensing and sampling techniques such as sub-bottom profiling, sidescan-sonar and bathymetric mapping, gravity core and grab sampling, and photography. These data were used to define the surficial sediment distribution, underlying structure and sea floor morphology of the study area. The primary focus of this report is to present a georeferenced, digital sidescan-sonar mosaic of the study region. The sidescan-sonar data were acquired with the AMS-120 (120kHz) sidescan-sonar system during USGS cruise F9-89-NC. The dataset covers approximately 1000 km² of the continental shelf between Point Reyes, California and Half Moon Bay, California, extending west to the continental shelf break near the Farallon Islands. The sidescan-sonar mosaic displays a heterogenous sea-floor environment, containing outcropping rock, ripples, dunes, lineations and depressions, as well as flat, featureless sea floor (Karl and others, 2002). These data, along with sub-bottom interpretation and ground truth data define the geologic framework of the region. The sidescan-sonar mosaic can be used with supplemental remote sensing and sampling data as a base for future research, helping to define the local current regime and predominant sediment transport directions and forcing conditions within the Gulf of Farallones. Contents The contents of this report are as follows: Top-level Directory: > index.htm - This file is intended to be the starting point for accessing this report. It is written in the Hypertext Markup Language utilized by the World Wide Web (WWW) project and must be opened with a WWW browser. Once opened, the user may browse the report's contents as he or she would browse pages from the WWW. > readme.txt - ASCII text file containing a description of this report. This file may be viewed or printed with any system program capable of opening an ASCII text file. DIRECTORIES and SUB-DIRECTORIES: > arcgis - this directory contains the ESRI ArcGIS ArcMap 8.3 map file, ofr2004_1082.mxd and an ArcView 3.3 project file, ofr2004_1082.apr. The'Farallones' Data Frame layer within ofr2004_1082.mxd and the 'Farallones' View within ofr2004_1082.apr are projected in the following coordinate system: UTM, WGS84 datum, Zone 10, meters. All raster image and grid data are also projected in this same UTM coordinate system. All point and vector data are stored in decimal degrees. The arcgis directory also contains the following subdirectories: >> coastal_relief - contains a sun-illuminated TIFF image of the National Geophysical Data Center (NGDC) Coastal Relief Model >> metadata - contains the metadata for all the files utilized within the project file >> mosaic- contains the following sidescan-sonar mosaic files: farallones.tif/farallones.tfw - full resolution TIFF image (4 meter/pixel) farallones.sid/farallones.sdw - LizardTech's MrSID Version 1.4 image compression software image file >> shape- contains contour and trackline shapefiles found within the MXD and APR files > html - contains all HTML pages accessed within this report, and sub-directories: images - contains the image files utilized within HTML pages; and PDF - contains PDF version of Figures > ivs- contains a 3-D scene file viewable with Fledermaus or iView3D and a 'fly-through' mpeg movie file System Requirements This report can be successfully accessed on systems utilizing the following operating systems: Microsoft Windows, Macintosh and UNIX. The ESRI ArcMap map file, ofr2004_1082.mxd will run only on Microsoft Windows systems, whereas the ArcView project file, ofr2004_1082.apr, will run on both Microsoft Windows systems and a UNIX platform. Disclaimer This report was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make 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. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this report 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.