H11043_GEO_WGS84_ENHAN.TIF: Enhanced composite sidescan sonar mosaic of NOAA survey H11043 off Branford, Connecticut

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?

Title:

H11043_GEO_WGS84_ENHAN.TIF: Enhanced composite sidescan sonar mosaic of NOAA survey H11043 off Branford, Connecticut

Abstract:

The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology.

Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted sidescan sonar mosaics (complete-coverage acoustic images of the sea floor) within specific areas of special interest. The mosaic presented herein covers a 41.1 km square area of the sea floor in north-central Long Island Sound off Branford, Connecticut.

The mosaics and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.

Supplemental_Information:

This image has been radiometrically processed to enhance the image for better viewing. High dn values represent high backscatter and low dn values represent low backscatter.

1. How should this data set be cited?

   U.S. Geological Survey, and National Oceanic and Atmospheric Administration, 2003, H11043_GEO_WGS84_ENHAN.TIF: Enhanced composite sidescan sonar mosaic of NOAA survey H11043 off Branford, Connecticut: U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole, MA.

   Online Links:

   • <http://pubs.usgs.gov/of/2004/1003/data/sidescan/h11043/enhanced/h11043_geo_wgs84_enhan.zip>

   Other_Citation_Details: Data are released via CD-ROM media.

   This is part of the following larger work.

   Poppe, L.J., Paskevich, V.F., Moser, M.S., DiGiacomo-Cohen, M.L., and Christman, E.B., 2004, Sidescan Sonar Imagery and Surficial Geologic Interpretation of the Sea Floor off Branford, Connecticut: Open-File Report 2004-1003, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

   Online Links:

   • <http://pubs.usgs.gov/of/2004/1003>
   • <http://woodshole.er.usgs.gov/openfile/of2004-1003>

   Other_Citation_Details:

   This digital publication may also be available via the web at pubs.usgs.gov

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -72.869907

   East_Bounding_Coordinate: -72.775833

   North_Bounding_Coordinate: 41.237200

   South_Bounding_Coordinate: 41.151200

3. What does it look like?

   h11043_geo_wgs84_enhan (GIF)

   Overview of the digital sidescan sonar mosaic produced for NOAA survey H11043

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

   Calendar_Date: 2001

   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 9524 x 8076 x 1, type Pixel

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      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?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
   • National Oceanic and Atmospheric Administration

2. Who also contributed to the data set?

   The U.S. Geological Survey (USGS) and National Oceanic and Atmospheric Administration (NOAA) must be acknowledged as the originators of this data set.

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

   Larry Poppe
   U.S. Geological Survey
   Geologist
   U.S. Geological Survey
   Woods Hole, MA 02543-1598
   USA
   

   (508) 548-8700 x2314 (voice)
   (508) 457-2310 (FAX)
   lpoppe@usgs.gov
   

This GIS overlay is a component of the Branford Survey, Long Island Sound, ArcView GIS database and contains the completed sidescan sonar mosaic for the study area. The image, which has been stretched to bring out details and facilitate interpretation, has a white background surrounding the composite mosaic.

1. From what previous works were the data drawn?

   h11043mosaic.tif (source 1 of 1)

   National Oceanic and Atmospheric Administration, Unpublished Material, h11043_utm18_wgs84.tif.

   Type_of_Source_Media: CD-ROM

   Source_Contribution:

   Original sidescan sonar mosaic created by National Oceanic and Atmospheric Administration (NOAA).

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

   Date: 2002 (process 1 of 4)

   The sidescan sonar imagery contained in this report was produced from data collected during 2001 as part of NOAA surveys H11043 and H11044 aboard the NOAA Ship RUDE. The data for these surveys were acquired in XTF (extended Triton data format) using an Edgetech (EG&G) 272T sidescan sonar tow fish set to sweep about 100 m to either side of the ship's track. The Edgetech model 272T tow fish emits two 50°-wide beams tilted down 20° from horizontal, and transmits at 100 kHz. Analog side scan sonar data were converted to digital using an EG&G Analog Converter Interface (ACI). These digital data were then recorded through a Triton Elics International ISIS data acquisition system.

   The sidescan sonar data were multiplexed and filtered to convert the data into the desired processing format and to remove speckle noise and corrected for slant-range distortions. and imported into SonarWeb, an application that creates mosaics from raw XTF sidescan sonar data. The mosaic include the following standards: 1 meter resolution, image 'shine through', and auto contrast adjustment (with a 12.9% contrast increase).

   The image includes a white background (no data) surrounding the sidescan sonar image. High dn values represent low backscatter and low dn values represent high backscatter.

   Person who carried out this activity:
   

   LTJG Marc Moser
   National Oceanic and Atmospheric Administration
   Field Support Liaison
   Hydrographic Systems and Technology Program
   Norfolk, VA 23510
   USA
   

   (757) 441-6726 (voice)
   Marc.S.Moser@noaa.gov
   

   Data sources used in this process:

   • XTF sidescan sonar data

   Data sources produced in this process:

   • H11043mosaic.tif
   • H11043mosaic.tfw

   Date: Unknown (process 2 of 4)

   The original image was renamed to h11043_utm18_wgs84 for archival purposes and to be more descriptive.

   Person who carried out this activity:
   

   Lawrence J. Poppe
   U.S. Geological Survey
   Geologist
   384 Woods Hole Road
   Woods Hole, MA 02543-1598
   USA
   

   (508) 548-8700 x2314 (voice)
   (508) 457-2310 (FAX)
   lpoppe@usgs.gov
   

   Data sources used in this process:

   • H11043mosaic.tif
   • H11043mosaic.tfw

   Data sources produced in this process:

   • h11043_utm18_wgs84.tif
   • h11043_utm18_wgs84.tfw

   Date: 26-Sep-2003 (process 3 of 4)

   The original image was projected from UTM zone 18 to geographic and greyscale inverted. Lower digital values (dark) represent low backscatter and higher digital values represent high backscatter.

   Person who carried out this activity:
   

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

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

   Data sources used in this process:

   • h11043_utm18_wgs84.tif
   • h11043_utm18_wgs84.tfw

   Data sources produced in this process:

   • h11043_geo_wgs84.tif
   • h11043_geo_wgs84.tfw

   Date: 26-Sep-2003 (process 4 of 4)

   A linear contrast stretch was applied to the image to brighten and enhance the image for better viewing and visual interpretation. The final image was saved in GEOTIFF format.

   Person who carried out this activity:
   

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

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

   Data sources used in this process:

   • h11043_geo_wgs84.tif
   • h11043_geo_wgs84.tfw

   Data sources produced in this process:

   • h11043_geo_wgs84_enhan.tif
   • h11043_geo_wgs84_enhan.tfw

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

1. How well have the observations been checked?

   There are no attributes associated with a GEOTIFF image.

2. How accurate are the geographic locations?

   Navigation was by differential GPS; positional accuracy to less than 10 m.

3. How accurate are the heights or depths?

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

   All collected data were processed and used to generate the digital mosaic.

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

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

Access_Constraints: None

Use_Constraints:

Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration as the originators of this dataset.

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

   Larry Poppe
   U.S. Geological Survey
   Geologist
   U.S. Geological Survey
   Woods Hole, MA 02543-1598
   USA
   

   (508) 548-8700 x2314 (voice)
   (508) 457-2310 (FAX)
   lpoppe@usgs.gov
   

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

   h11043_geo.tif

3. What legal disclaimers am I supposed to read?

   Although this data set has been used by the USGS and NOAA, no warranty, expressed or implied, is made by the USGS or NOAA 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 or NOAA in the use of these data or related materials.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Two files: h11043_geo.tif and h11043_geo.tfw in format TIFF Size: 75.152 Kb
     Media you can order:	CD-ROM (Density 650 Mbytes) (format ISO 9660) Note: The user must have a CD-ROM capable of reading an ISO 9660 standard CD-ROM

   • Cost to order the data: None

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

   The user must have a program capable of reading and processing "geotiff" images.

Dates:

Last modified: 04-Apr-2004

Metadata author:

Lawrence J. Poppe
U.S. Geological Survey
Geologist
U.S. Geological Survey
Woods Hole, MA 02543-1598
USA

(508) 548-8700 x2314 (voice)
(508) 457-2310 (FAX)
lpoppe@usgs.gov

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)