David Twichell 2005 remote-sensing image Open-File Report 2005-1071 Woods Hole Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program Twichell D.C.Cross V.A.Paskevich, V.F.Hutchinson, D.R.Winters, W.J.Hart, P.E.20051.0http://pubs.usgs.gov/of/2005/1071Open-File Report2005-1071Woods Hole Science Center, Woods Hole, MAU.S. Geological Survey, Coastal and Marine Geology Program1 DVD-ROM http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.zip seamarc_enutm.tif1.0Valerie Paskevich Since 1982, the U.S. Geological Survey (USGS) has collected a large amount of surficial and shallow subsurface geologic information in the deep parts of the Gulf of Mexico. These data include digital sidescan sonar imagery, digital seismic-reflection data, and descriptions and analyses of piston and gravity cores. The data were collected during several different projects that addressed surficial and shallow subsurface geologic processes. Some of these data sets have already been published, but the growing interest in the occurrence and distribution of gas hydrates in the Gulf of Mexico warrants integrating these existing data and associated interpretations into a GIS to provide regional background information for ongoing and future gas hydrate research. This GIS data layer is a 25 m version of the completed SeaMARC 1A sidescan sonar image mosaic, which has been enhanced and projected to UTM Zone 16 using the WGS 84 datum. The SeaMARC 1A imagery was collected in 1990 from the eastern part of the Mississippi Fan and covers an area of 3,047 km2. An interpretation of these data is presented by Twichell et al. (1992) and Twichell et al. (1995). en 19900325 19900408 ground condition Complete None planned -86.602758 -84.986524 26.900431 26.100683 539716.804203699991.8042032888369.8766852975469.876685 General U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP Woods Hole Science Center WHSC Gulf of Mexico database U.S. Exclusive Economic Zone EEZ sidescan sonar sidescan sonar mosaic composite mosaic TIFF TIF GEOTIFF GeoTIFF SeaMARC 1A seamarc Information Archives Field Activity 99002 ISO 19115 Topic Category oceans and estuaries imageryBaseMapsEarthCover geoscientificInformation General Gulf of Mexico Mississippi Fan North America United States None Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 V. Paskevich D. Twichell W. Schwab 2001 Open-File Report 00-352 Woods Hole Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program http://pubs.usgs.gov/of/of00-352/ 1 CD-ROM1.0 V. Paskevich 1992 Open-File Report 92-536 Woods Hole Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program 1.0 Twichell, D.C. Schwab, W.C. Nelson, C.H. Kenyon, N.H. Lee, H.J. 1992 Geology v. 20, p. 689-692 Boulder, CO Geological Society of America Twichell, D.C. Schwab, W.C. Kenyon, N.H. 1995 Atlas of deep water environments architectural style in turbidite systems p. 282-286 London Chapman and Hall Raster DatasetThumbnail image of the SeaMARC1A sidescan sonar mosaic from the Mississippi Fan.GIFhttp://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm-thumb.gifOverview image of the SeaMARC1A sidescan sonar mosaic from the Mississippi Fan.GIFhttp://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.gif All these data were collected with a SeaMARC 1A sidescan sonar system operated by Williamson and Associates, Seattle, WA. All the data were acquired at a 5 km total swath width. All imagery that was acquired has been included in this mosaic. The ship was navigated using satellite navigation, and the location of the sidescan vehicle was computed using the ship location, ship heading, length of tow cable, and depth of the sidescan vehicle. magnetic tape 19900325 19900408 ground condition SeaMARC 1A sidescan sonar data were logged using a QMIPS data acquisition system and recorded to 8 mm digital tape for post-cruise processing. QMIPS data tapes The individual SeaMARC 1A sidescan swaths were transferred from tape to disk. The files were subsequently converted from the QMIPS format to a WHIPS format for processing. The WHIPS format and processing procedures are described in Paskevich (1992). QMIPS data tapes WHIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The individual sidescan files were processed using the Woods Hole Image Processing Software (WHIPS, Paskevich, 1992). The individual strips of sidescan data were processes to apply geometric (i.e. slant-to-ground range corrections) and radiometric corrections (i.e. beam correction shading and striped noise removal). WHIPS data files WHIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The SeaMARC 1A files that comprised the eastern half of the survey were transferred to the Woods Hole Science Center's MicroVAX-II computer system. This portion of the survey consisted of mostly straight line segments and were to be digitally mosaicked on this system. (The western portion was done a few months later with developing software). The MicroVAX-II computer system contained the Mini-Image Processing System (MIPS) software that was needed to map and digitally mosaic the data. To begin processing, the WHIPS data files were all converted to MIPS format. WHIPS data files MIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The MIPS data files were spatially mapped using program GEOM. The files were projected and mapped with a Mercator projection and a Clarke 1866 spheroid. WHIPS data files MIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov As the individual swaths were mapped, they were geo-referenced to the base image, stenciled and mosaicked to the base. (The base was one swath that had been mapped and was selected as the master which everything would be registered with). Control points were selected interactively to match features on the adjacent lines and a rubber sheeting procedure was applied to the mapped swaths to better align the images. Once registered, a stencil line was interactively drawn around the area of the line to be added. This stencil area was critical as it not only eliminated the unwanted area that was overlapping the adjacent lines, but defined the area to be kept. Finally, the registered, transformed and stenciled image was added to the base. These steps were repeated for each swath until the eastern mosaic was completed. MIPS data files MIPS data files David Twichell U.S. Geological Survey Oceanographer (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The SeaMARC1A files that comprised the western half of the survey were mapped using the WHIPS software. This area of the survey consisted of several survey line segments. This software could handle curved line segments./ The files were projected and mapped with a Mercator projection and a Clarke 1866 spheroid to match the eastern portion of the mosaic. MIPS data files MIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The WHIPS mapped swaths were transferred to the Center's MicroVAX-II computer system for stenciling and mosaicking with the MIPS software. Once transferred to the MicroVAX, the files were converted to the MIS format for processing. WHIPS data files MIPS data files David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The converted WHIPS mapped swaths were stenciled and mosaicked with the MIPS software. This procedure is similar to the one outlined for the eastern portion of the survey. Control points were selected interactively to match features on the adjacent lines and a rubber sheeting procedure was applied to the mapped swaths to better align the images. Once registered, a stencil line was interactively drawn around the area of the line to be added. This stencil area was critical as it not only eliminated the unwanted area that was overlapping the adjacent lines but defined the area to be kept. Finally the registered, transformed and stenciled image was added to the base. These steps were repeated for each swath until the western mosaic was completed. MIPS data files west.pic David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The two completed mosaics, east.pic and west.pic, were combined to create one overall view of the study area. east.pic west.pic compos.pic David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The MIPS created mosaic, compos.pic, was transferred to a UNIX computer system. The image was imported into a PCI Remote Sensing database file and georeferenced as Mercator. compos.pic msfan.pix David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov The mosaic, compos.pix, was reprojected from Mercator to UTM using the PCI Remote Sensing software. msfan.pix 19990218 utme00.pix Valerie Paskevich U.S. Geological Survey Information Specialist/GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov Using the PCI Remote Sensing software, a linear contrast stretch was applied to the SeaMARC 1A sidescan sonar mosaic stored in channel 1. This was done to improve the image's viewing by expanding the data's dynamic range. utm1.pix channel 1 19990319 utm1.pix channel 3 Valerie Paskevich U.S. Geological Survey Information Specialist/GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov The completed, enhanced, 25 m SeaMARC 1A sidescan sonar mosaic was exported from the PCI 'pix' database as a GeoTIFF image with an associated "world" file. utme00.pix channel 3 20000302 raw/seamarc.tif Valerie Paskevich U.S. Geological Survey Information Specialist/GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov The SeaMARC 1A GeoTIFF image was reprojected from a UTM projection using the NAD 27 datum to a UTM projection (zone 16) using the WGS 84 datum. The reprojection was done using Geographic Transformer (v. 5.1) produced by Blue Marble. The affine transform mode was used, the pixel size was 25 m, and the central latitude was 26.25N. enhanced/seamarc.tif 20040916 seamarc_enutm.tif David Twichell U.S. Geological Survey Oceanographer mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2266 (508) 457-2310 dtwichell@usgs.gov There are no attributes associated with the image. Raster Pixel 3484 6411 1 25.00000025.0000008Upper LeftTRUEPackBits1pixel codesFALSETIFFmetersmeters0GeoTIFF row and column 25.000000 25.000000 meters Universal Transverse Mercator160.999600-87.0000000.000000500000.0000000.000000 D_WGS_1984 WGS_1984 6378137.000000 298.257224 GCS_WGS_1984WGS_1984_UTM_Zone_16N Band_1 Table256 ObjectID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Value Red Green Blue Greyscale digital sidescan sonar SeaMARC 1A composite mosaic from the Mississippi Fan, Gulf of Mexico. Pixel values contain acoustic reflectivity values normalized to an 8-bit data range (0-255). Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values).There are no attributes associated with a GeoTIFF image. Valerie Paskevich U.S. Geological Survey Information Specialist/GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov Downloadable Data Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. TIFF zip 0.000 4.919GeoTIFFA GeoTIFF image and associated world file. DVD-ROM 4.75GbytesUDF http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.zipData may be retrieved via any WWW browser. None This image is available as a GeoTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GEOTIFF image. 20050222 U.S. Geological Survey Valerie Paskevich Information Specialist / GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time None None enhttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535seamarc_enutm.tif539716.804203699991.8042032975469.8766852888369.8766851-86.602758-84.98652426.90043126.1006831ISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset002file://\\VEECRODTXP\E$\pubs_in_progress\gomgis\data\sidescan\imagery\seamarc\enhanced\utm\seamarc_enutm.tifLocal Area Network4.919Raster DatasetWGS_1984_UTM_Zone_16N21641125Meter1 Meter = 1 Meter(s)348425Meter1 Meter = 1 Meter(s)2005121309381500200512130938150020051213