U.S. Geological Survey Open-File Report 98-590


Jane F. Denny1
William Schwab1

1U.S. Geological Survey, Woods Hole Field Center, 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.

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 a user to access the information by using a variety of WWW information browsers (i.e. NCSA Mosaic, Netscape) to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'index.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.

Also, some links to USGS collaborators and other agencies are available on this CD-ROM. These links are only accessible if access to the Internet is available during browsing of the CD-ROM.

The archived sidescan-sonar data may be downloaded and processed. There is software available on this CD-ROM for viewing an individual swath using any computer running the UNIX operating system. See the "readme" file in the BIN directory for details.


This CD-ROM contains copies of the navigation and field sidescan-sonar data collected aboard the F/V Alpha & Omega II. Cruise 98013 was conducted from September 10 to September 23, 1998, and is an on-going collaborative field program involving  the USGS Woods Hole Field Center and the U.S Army Corps of Engineers, New York District.

In 1995, the USGS, in cooperation with the U.S Army Corps of Engineers (USACOE), New York District, began a program to generate reconnaissance maps of the sea floor offshore of the New York-New Jersey metropolitan area, one of the most populated coastal regions of the United States. The goal of this mapping program is to provide a regional synthesis of the sea-floor environment, including a description of sedimentary environments, sediment texture, sea-floor morphology, and geologic history to aid in understanding the impacts of anthropogenic activities, such as ocean dumping.   This mapping effort differs from previous studies of this area by obtaining digital, sidescan-sonar images that cover 100 percent of the sea floor. 

This investigation was motivated by the need to develop an environmentally acceptable solution for the disposal of dredged material from the New York - New Jersey Port,  identify potential sources of sand for renourishment of the southern shore of Long Island, and by the opportunity to develop a better understanding of the transport and long-term fate of contaminants by investigations of the present distribution of materials discharged into the New York Bight over the last 100+ years.

Sidescan-sonar data collected in May 1995 and May 1996 (USGS Cruises Seax95007 and Seax96004, respectively) were digitally mosaicked to provide a base suitable for use in Geographic Information Systems of the New York Bight Apex region (Schwab, et. al., 1997).  The data collected during USGS Cruise ALPH98013 augment the New York Bight Apex Mapping Project by extending the sidescan-sonar and seismic reflection coverage to the east in a  ~ 23 km by ~32 km area. These data will be instrumental in developing a more comprehensive understanding of the inner shelf geology within the New York Bight Apex.


Directory DATA:

The DATA Directory ontains the raw sidescan-sonar data. These data were collected using a Datasonics100-kHz sidescan-sonar system and were logged on a Triton Technologies, Inc., ISIS system. The sidescan-sonar data were collected at a range of 187.5 meters per side, with the exception of test1 - l4f3, and l8f2 - l25f1, which were collected at a range of 93.75 meters per side. The sidescan-sonar data are 16-bit binary; the format is summarized in a text file located in the DOC directory. The data description is also available in HTML format. The archived sidescan-sonar data are stored on 44 separate CD-ROMs.  Go to the Field Data from the main page to access these data.

Note:    The Julian Day stored in the header of  Lines l1f1 - l12f1 is incorrect; the JD is off by one day. For example, l1f1 lists the JD as 253, it should be 254;  l7f1 lists 254 as the JD, but it should be 255. The offset was corrected as of  l12f2. The JD offset was caused by an incorrect internal date within the ISIS acquisition system, resulting in an incorrect JD recorded to the sidescan-sonar header. As long as the user is aware of the error, there should not be a problem in manipulating the data.

Directory DOC:

The DOC Directory contains ASCII documentation on the sidescan-sonar data file formats collected using the ISIS system. This directory also contains ASCII copies of the cruise report and a description of the navigation data files contained in the NAV directory.

Directory NAV:

The NAV Directory contains the navigation data that were collected during the sidescan-sonar component of the field program using a USGS differential GPS system manufactured by Ashtech.  Differential corrections were obtained from shore-based U.S. Coast Guard beacons. WARNING: These data have not been checked for errors. Use with caution.

    NAV sub-directory:

The files in this directory have been reformatted from the original raw navigation data file using the UNIX awk utility (the awk script file is located in the SCRIPTS sub-directory) to allow for easier viewing.

Every navigation fix from the original raw data has been preserved.

The navigation is stored in ASCII files with six fields separated by tabs. Each file represents a separate cruise day (i.e. jd128web.txt). Navigaton fixes are at 10 second intervals.

Field 1: Date and Time (julian day:hour (UTC):minute:second)
Field 2: Latitude (ie. 32d59375 )
Field 3: Longitude (ie. -79d968975)
Field 4: Speed (computed from the navigation)
Field 5: Heading (computed from the navigation)
Field 6: Water Depth (derived from a Furuno dual-frequency fathometer). ** Depths are in meters, but have not been corrected for the depth of the transducer, which was about 2 m below the sea surface, nor for the tide (for tidal information, see

    RAWNAV sub-directory:

The raw USGS differential GPS data is located in this directory. These files (i.e. jd128) represent the data as originally recorded on floppy disk aboard ship. The data are in NEMA format and contain the $GPGGA string.

    SCRIPTS sub-directory:

The SCRIPTS sub-directory contains an awk script file used to reformat the raw navigation into a format more suitable for on-screen viewing and printing. See the readme.txt file in this sub-directory for details.

Directory HTMLDOCS:

The HTMLDOCS Directory contains the necessary HTML files and supporting graphics to allow the user access to the CD-ROM via any World Wide Web (WWW) browser.

Directory PLOTS:

    POSTSCRIPT sub-directory:

    The POSTSCRIPT sub-directory contains the PostScript navigation plots.

    GIFS sub-directory:

    The GIFS sub-directory contains the navigation plots in Compuserve GIF format.

Directory BIN:

The BIN Directory contains the ShowImage program to view the raw data files on screen. The program only runs on systems using the UNIX operating system. Included are three separate sub-directories containing the executable for the appropriate operating system: sgi, digunix, linux. See the readme.txt file in this directory for details.

Directory IMAGES:

The IMAGES Directory contains GIF and TIFF images that are used by HTML hyperlinks.


Danforth, W.W., 1997, Xsonar/ShowImage: A Complete System for Rapid Sidescan-Sonar Processing and Display, U.S. Geological Survey Open-File Report 97-686, pp 1 - 79.

Schwab, W.C., Corso, W., Allison, M.A., Butman, B., Denny, J.F., Lotto, L., Danforth, W.W., Foster, D.S., O'Brien, T.F., Nichols, D.A., Irwin, B.J., and Parolski, K.F., 1997, Mapping the Sea Floor Geology Offshore of the New York-New Jersey Metropolitan Area Using Sidescan-Sonar: Preliminary Report,  U.S. Geological Survey Open-File Report 97-61, 3 Sheets.


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, 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 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 these data, software, or related materials.

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