### SEAMARC_ENUTM.TIF - Enhanced 25 m SeaMARC 1A sidescan sonar mosaic from the Mississippi Fan (UTM, Zone 16, WGS84)

Metadata also available as - [Outline] - [Parseable text]

#### Frequently-anticipated questions:

- What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
- Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
- Why was the data set created?
- How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
- How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
- How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
- Who wrote the metadata?

### What does this data set describe?

Title:
  SEAMARC_ENUTM.TIF - Enhanced 25 m SeaMARC 1A sidescan sonar mosaic from the Mississippi Fan (UTM, Zone 16, WGS84)
Abstract:
  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.

1. How should this data set be cited?

   > Twichell, David, and Paskevich, Valerie, 2005, SEAMARC_ENUTM.TIF - Enhanced 25 m SeaMARC 1A sidescan sonar mosaic from the Mississippi Fan (UTM, Zone 16, WGS84): Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Online Links:

   > - <http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.zip>

   This is part of the following larger work.

   > D.C., Twichell, V.A., Cross, Paskevich, V.F., Hutchinson, D.R., Winters, W.J., and Hart, P.E., 2005, GIS of selected geophysical and core data in the northern Gulf of Mexico continental slope collected by the U.S. Geological Survey: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Online Links:

   > - <http://pubs.usgs.gov/of/2005/1071>

   Other_Citation_Details: 1 DVD-ROM

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -86.602758
   East_Bounding_Coordinate: -84.986524
   North_Bounding_Coordinate: 26.900431
   South_Bounding_Coordinate: 26.100683

3. What does it look like?

   <http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm-thumb.gif> (GIF)
     Thumbnail image of the SeaMARC1A sidescan sonar mosaic from the Mississippi Fan.
   <http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.gif> (GIF)
     Overview image of the SeaMARC1A sidescan sonar mosaic from the Mississippi Fan.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 25-Mar-1990
   Ending_Date: 08-Apr-1990
   Currentness_Reference: ground condition

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: remote-sensing image

6. How does the data set represent geographic features?

   1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      - Dimensions 3484 x 6411 x 1, type Pixel

   2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
        UTM_Zone_Number: 16
        Transverse_Mercator:
          Scale_Factor_at_Central_Meridian: 0.999600
          Longitude_of_Central_Meridian: -87.000000
          Latitude_of_Projection_Origin: 0.000000
          False_Easting: 500000.000000
          False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 25.000000
      Ordinates (y-coordinates) are specified to the nearest 25.000000
      Planar coordinates are specified in meters

      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

7. How does the data set describe geographic features?

   `Band_1`

     `ObjectID`
       Internal feature number. (Source: ESRI)

       Sequential unique whole numbers that are automatically generated.

     `Value`

     `Red`

     `Green`

     `Blue`

   Entity_and_Attribute_Overview: There are no attributes associated with a GeoTIFF image.

### Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

   - David Twichell
   - Valerie Paskevich

2. Who also contributed to the data set?

3. To whom should users address questions about the data?

   David Twichell
   U.S. Geological Survey
   Oceanographer
   384 Woods Hole Road
   Woods Hole, MA 02543-1598
   USA

   (508) 548-8700 x2266 (voice)
   (508) 457-2310 (FAX)
   dtwichell@usgs.gov

### Why was the data set created?

> 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).

### How was the data set created?

1. From what previous works were the data drawn?

   QMIPS data tapes (source 1 of 1)

     > ,.

     Type_of_Source_Media: magnetic tape
     Source_Contribution:
       SeaMARC 1A sidescan sonar data were logged using a QMIPS data acquisition system and recorded to 8 mm digital tape for post-cruise processing.

2. How were the data generated, processed, and modified?

   (process 1 of 14)
     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).

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - QMIPS data tapes

     Data sources produced in this process:

     - WHIPS data files

   (process 2 of 14)
     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).

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - WHIPS data files

     Data sources produced in this process:

     - WHIPS data files

   (process 3 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - WHIPS data files

     Data sources produced in this process:

     - MIPS data files

   (process 4 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - WHIPS data files

     Data sources produced in this process:

     - MIPS data files

   (process 5 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - MIPS data files

     Data sources produced in this process:

     - MIPS data files

   (process 6 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - MIPS data files

     Data sources produced in this process:

     - MIPS data files

   (process 7 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - WHIPS data files

     Data sources produced in this process:

     - MIPS data files

   (process 8 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - MIPS data files

     Data sources produced in this process:

     - west.pic

   (process 9 of 14)
     The two completed mosaics, east.pic and west.pic, were combined to create one overall view of the study area.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - east.pic
     - west.pic

     Data sources produced in this process:

     - compos.pic

   (process 10 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - compos.pic

     Data sources produced in this process:

     - msfan.pix

   Date: 18-Feb-1999 (process 11 of 14)
     The mosaic, compos.pix, was reprojected from Mercator to UTM using the PCI Remote Sensing software.

     Person who carried out this activity:

     Valerie Paskevich
     U.S. Geological Survey
     Information Specialist/GIS Coordinator
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2281 (voice)
     (508) 457-2310 (FAX)
     vpaskevich@usgs.gov

     Data sources used in this process:
     - msfan.pix

     Data sources produced in this process:

     - utme00.pix

   Date: 19-Mar-1999 (process 12 of 14)
     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.

     Person who carried out this activity:

     Valerie Paskevich
     U.S. Geological Survey
     Information Specialist/GIS Coordinator
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2281 (voice)
     (508) 457-2310 (FAX)
     vpaskevich@usgs.gov

     Data sources used in this process:
     - utm1.pix channel 1

     Data sources produced in this process:

     - utm1.pix channel 3

   Date: 02-Mar-2000 (process 13 of 14)
     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.

     Person who carried out this activity:

     Valerie Paskevich
     U.S. Geological Survey
     Information Specialist/GIS Coordinator
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2281 (voice)
     (508) 457-2310 (FAX)
     vpaskevich@usgs.gov

     Data sources used in this process:
     - utme00.pix channel 3

     Data sources produced in this process:

     - raw/seamarc.tif

   Date: 16-Sep-2004 (process 14 of 14)
     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.

     Person who carried out this activity:

     David Twichell
     U.S. Geological Survey
     Oceanographer
     384 Woods Hole Road
     Woods Hole, MA 02543-1598
     USA

     (508) 548-8700 x2266 (voice)
     (508) 457-2310 (FAX)
     dtwichell@usgs.gov

     Data sources used in this process:
     - enhanced/seamarc.tif

     Data sources produced in this process:

     - seamarc_enutm.tif

3. What similar or related data should the user be aware of?

   > Paskevich, V., Twichell, D., and Schwab, W., 2001, SeaMARC 1A sidescan sonar mosaic, cores and depositional interpretation of the Mississippi Fan: ArcView GIS data release: Open-File Report 00-352, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Online Links:

   > - <http://pubs.usgs.gov/of/of00-352/>

   Other_Citation_Details: 1 CD-ROM

   > Paskevich, V., 1992, Digital mapping of side-scan sonar data with the Woods Hole Image Processing System software: Open-File Report 92-536, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   > Twichell, D.C., Schwab, W.C., Nelson, C.H., Kenyon, N.H., and Lee, H.J., 1992, Depositional processes on the distal Mississippi Fan: Geology v. 20, p. 689-692, Geological Society of America, Boulder, CO.

   > Twichell, D.C., Schwab, W.C., and Kenyon, N.H., 1995, Geometry of sandy deposits at the distal edge of the Mississippi Fan, Gulf of Mexico: Atlas of deep water environments architectural style in turbidite systems p. 282-286, Chapman and Hall, London.

### How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

   There are no attributes associated with the image.

2. How accurate are the geographic locations?

   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.

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   All imagery that was acquired has been included in this mosaic.

5. How consistent are the relationships among the observations, including topology?

   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.

### How can someone get a copy of the data set?

> Are there legal restrictions on access or use of the data?

> > Access_Constraints: None
> > Use_Constraints:
> >   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.

1. Who distributes the data set? (Distributor 1 of 1)

   Valerie Paskevich
   U.S. Geological Survey
   Information Specialist/GIS Coordinator
   384 Woods Hole Road
   Woods Hole, MA 02543-1598
   USA

   (508) 548-8700 x2281 (voice)
   (508) 457-2310 (FAX)
   vpaskevich@usgs.gov

2. What's the catalog number I need to order this data set?

   `Downloadable Data`

3. What legal disclaimers am I supposed to read?

   > 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.

4. How can I download or order the data?

   - Availability in digital form:

     Data format: | A GeoTIFF image and associated world file. in format TIFF GeoTIFF Size: 0.000
     Network links: | <http://pubs.usgs.gov/of/2005/1071/data/sidescan/imagery/enhanced/utm/seamarc_enutm.zip>
     Media you can order: | DVD-ROM (Density 4.75 Gbytes) (format UDF)

   - Cost to order the data: None

5. What hardware or software do I need in order to use the data set?

   > 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.

### Who wrote the metadata?

Dates:
  Last modified: 22-Feb-2005
Metadata author:
  U.S. Geological Survey
  c/o Valerie Paskevich
  Information Specialist / GIS Coordinator
  384 Woods Hole Road
  Woods Hole, MA 02543-1598
  USA

  (508) 548-8700 x2281 (voice)
  (508) 457-2310 (FAX)
  vpaskevich@usgs.gov

Metadata standard:
  FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:
  - <http://www.esri.com/metadata/esriprof80.html>

Generated by `mp` version 2.8.6 on Tue Dec 13 09:41:45 2005