GLORIA SIDESCAN SONAR FIELD DATA AND NAVIGATION DATA COLLECTED IN THE GULF OF MEXICO DURING R/V FARNELLA CRUISES IN 1982 AND 1985 U.S. Geological Survey Open-File Report 96-707 by David C. Twichell and Valerie Paskevich US Geological Survey Woods Hole, MA 02543 This CD-ROM (Compact Disc-Read Only Memory) has been produced in accordance with the ISO 9660 CD-ROM standard and is therefore capable of being read on any computing platform that has appropriate CD-ROM driver software installed. DISCLAIMER This 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, 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 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. Errors and inconsistencies for concentration units other than parts per billion (ppb), sample type coding, sample location, and the like are known to exist. Introduction This CD-ROM contains copies of the navigation and field sidescan sonar data collected in the Gulf of Mexico during four cruises aboard the R/V FARNELLA. The cruises, conducted during February, 1982 and August through October, 1985, were part of the USGS Exclusive Economic Zone mapping program (EEZ-SCAN) which was a cooperative program between the US Geological Survey and the Institute of Oceanographic Sciences of the UK. The survey area included the entire US Exclusive Economic Zone of the Gulf of Mexico seaward of approximately 400 m water depth (EEZ-SCAN 85, Scientific Staff, 1987; Twichell and Polloni, 1993). There are seven directories on this CD-ROM. These directories include: 1. Directory REPORTS This directory contains copies of the cruise reports from the four cruises. Two of the cruise reports are compiled in one file. The cruise reports are are ASCII files listing the participants and a brief narrative summarizing the cruise. 2. Directory NAV This directory contains the navigation and bathymetry data collected during the four cruises. The files containing the navigation are: 1. FARN82-1.DAT 2 Feb. -24 Feb., 1982 (Julian days 33-55) 2. FARN85-1.DAT 7 Aug. - 3 Sept., 1985 (Julian days 219-246) 3. FARN85-2.DAT 5 Sept - 29 Sept., 1985 (Julian days 248-272) 4. FARN85-3.DAT 2 Oct. - 22 Oct., 1985 (Julian days 275-295) The navigation files are in ASCII format containing ten fields separated by spaces: Field 1: Latitude in decimal degrees. Field 2: Longitude in decimal degrees - minus sign for W long. Field 3: Year - 4 digits Field 4: Month - 1 or 2 digits Field 5: Day - 1 or 2 digits Field 6: Hour - 1 or 2 digits Field 7: Minute - 1 or 2 digits Field 8: Second - 1 or 2 digits Field 9: Depth in uncorrected meters - assuming a speed of sound of 1500 m/sec. When the fathometer was not operating, the two depth fields have a 0 value in them. Field 10: Depth in corrected meters - Matthews tables were used to make this correction for variations in the speed of sound in water (Matthews, 1939). Tidal corrections were not applied to these data. 3. Directory DOCUMENTATION Documentation of the sidescan sonar data format is summarized here. The sidescan data are presented in two different ways to make them available to a broader community of users. They are presented in an "unmerged" form and as netCDF files. 4. Directory GLORIA82 This directory contains the GLORIA sidescan sonar data collected during the Farnella cruise in February, 1982. Within this directory is an ASCII file titled "files" which lists the file prefixes, number of lines and samples in each file, start and end times, and start and end depths. An important note is that the data collected in 1982 were acquired using a 20 SECOND PULSE REPETITION RATE while the data collected in 1985 all used a 30 second pulse repetition rate. There are also two directories, "netcdf" and "unmerged" which contain the GLORIA field data in the two different forms summarized in the DOCUMENTATION directory. 5. Directory GLORIA85 This directory consists of three sub-directories containing the GLORIA sidescan sonar data collected during legs 1, 2 and 3 of the 1985 Gulf of Mexico surveys. leg1 - This directory contains the GLORIA sidescan sonar data collected during leg 1 of the Farnella cruises in 1985 (7 Aug. - 3 Sept., 1985). Within this directory is an ASCII file titled "files.TXT" which lists the file prefixes, number of lines and samples in each file, start and end times, and start and end depths. An important note is that the data collected in 1985 were acquired using a 30 SECOND PULSE REPETITION RATE while the data collected in 1982 used a 20 second pulse repetition rate. There are also two directories, "netcdf" and "unmerged" which contain the GLORIA field data in the two forms summarized in the DOCUMENTATION directory. leg2 - This directory contains the GLORIA sidescan sonar data collected during leg 2 of the Farnella cruises in 1985 (5 Sept - 29 Sept., 1985). Within this directory is an ASCII file titled "files.TXT" which lists the file prefixes, number of lines and samples in each file, start and end times, and start and end depths. An important note is that the data collected in 1985 were acquired using a 30 SECOND PULSE REPETITION RATE while the data collected in 1982 used a 20 second pulse repetition rate. There are also two directories, "netcdf" and "unmerged" which contain the GLORIA field data in the two forms summarized in the DOCUMENTATION directory. leg3 - This directory contains the GLORIA sidescan sonar data collected during leg 3 of the Farnella cruises in 1985 (2 Oct. - 22 Oct., 1985). Within this directory is an ASCII file titled "files.TXT" which lists the file prefixes, number of lines and samples in each file, start and end times, and start and end depths. An important note is that the data collected in 1985 was acquired using a 30 SECOND PULSE REPETITION RATE while the data collected in 1982 used a 20 second pulse repetition rate. There are also two directories, "netcdf" and "unmerged" which contain the GLORIA field data in the two forms summarized in the DOCUMENTATION directory. 6. Directory PLOTS This directory contains Encapsulated PostScript (EPS) and Compuserve Graphics Interchange Format (GIF) of the R/V Farnella survey track lines. GIF images showing tracklines of each leg separately are available. In addition, images showing tracklines of all four legs together are provided in both GIF and EPS formats. 7. Directory HTMLDOCS This directory contains the HyperText Markup Language (HTML) files and supporting graphics to allow user access to the CD-ROM via any World Wide Web browser. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Hardware and Software Requirements This CD-ROM (Compact Disc-Read Only Memory) has been produced in accordance with the ISO 9660 CD-ROM Standard and is therefore capable of being read on any computing platform that has appropriate CD-ROM driver software installed. No specific software is required to access this CD-ROM, nor is any software provided as part of the CD-ROM. Access to the data and information contained on this CD-ROM was developed using the HyperText Markup Language (HTML) utilized by the World Wide Web (WWW) project. Development of the CD-ROM documentation and user interface in HTML allows the user to access the information through a variety of WWW information browsers (i.e. NCSA Mosaic, Netscape, Microsoft Explorer) to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'intro.HTM' at the top level directory of this CD-ROM with your selected browser. The HTML documentation is written utilizing some HTML 3.0 enhancements. The disk should be viewable by all WWW browsers but may not properly format on some older WWW browsers. References Cited: EEZ-SCAN 85 Scientific Staff, 1987, Atlas of the U.S. Exclusive Economic Zone, Gulf of Mexico: U.S. Geological Survey Miscellaneous Investigation I-1864-A, 104 p. Matthews, D.J., 1939, Tables of the velocity of sound in pure water and sea water for use in echo sounding and echo ranging: Admiralty Hydrographic Dept., London, 52 p. Twichell, D.C., and Polloni, C.F., 1993, CD-ROM Atlas of the deepwater parts of the U.S. Exclusive Economic Zone in the Atlantic Ocean, the Gulf of Mexico, and the eastern Caribbean Sea: U.S. Geological Survey Digital Data Series DDS-15.