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BSCATxx.TIF, QUAD75 - Sidescan sonar images and quadrangle index of the shelf seafloor in the Monterey Bay area from Point Ano Nuevo to Point Sur, California

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Frequently-anticipated questions:


What does this data set describe?

    Title:
    BSCATxx.TIF, QUAD75 - Sidescan sonar images and quadrangle index of the shelf seafloor in the Monterey Bay area from Point Ano Nuevo to Point Sur, California
    Abstract:

    The sidescan sonar image of the shelf seafloor of the Monterey Bay area was mosaicked from data collected between 1995 and 1998 with three systems: Klein (towed), Simrad EM1000 (hull mounted), and EM300 (hull mounted). The resolution of the processed data ranged from 40 cm to 2.5 m. The data are presented here at a resolution of 2.5 m north of Monterey Canyon and 5 m south of Monterey Canyon. The sonar image is divided into 24 tiles that cover all or part of 7.5-minute map quandrangles. The polygon layer QUAD75 is an index for the 7.5-minute quadrangles.

    This is one of a collection of digital files of a geographic information system of spatially referenced data related to the USGS Coastal and Marine Geology Program "Monterey Bay National Marine Sanctuary Project" <http://walrus.wr.usgs.gov/mbms>. The data were collected and analyzed between 1994 and 2000.

  1. How should this data set be cited?

    P.S. Chavez, Jr., Isbrecht, J., Gabel, G., Galanis, P., Ross, S., Anima, R., Eittreim, S., Maher, N., Sides, S.C., Soltesz, D.L., Velasco, M.G., and Wong, Florence L. , 2001, BSCATxx.TIF, QUAD75 - Sidescan sonar images and quadrangle index of the shelf seafloor in the Monterey Bay area from Point Ano Nuevo to Point Sur, California:.

    Online Links:

    This is part of the following larger work.

    Wong, F.L., and Eittreim, S.E., 2001, Continental Shelf GIS for the Monterey Bay National Marine Sanctuary: U.S. Geological Survey Open-File Report 01-179, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.38230
    East_Bounding_Coordinate: -121.79293
    North_Bounding_Coordinate: 37.11902
    South_Bounding_Coordinate: 36.21493

  3. What does it look like?

    <http://geopubs.wr.usgs.gov/open-file/of01-179/images/bsimap.gif> (GIF)
    location map of backscatter images

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

    Beginning_Date: 1995
    Ending_Date: 1998
    Currentness_Reference: Ground Condition

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

    Geospatial_Data_Presentation_Form: map

  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 5585 maximum for 2.5-m pixel images. 3505 for 5-m images x 4522 maximum for 2.5-m pixels, 2267 for 5-m pixels, 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: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 500000.00
      False_Northing: 0.00

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 2.5 or 5
      Ordinates (y-coordinates) are specified to the nearest 2.5 or 5
      Planar coordinates are specified in meters

      The horizontal datum used is nad83.
      The ellipsoid used is GRS1980.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:

    Sidescan sonar data are presented as TIFF images where the pixel value represents the backscatter intensity of the sonar signal.

    Images BSCATxx.TIF for xx = 1 to 9, 10n, and 11n have 2.5-m pixel resolution with pixel values stretched and desampled from 1-m pixel Klein sidescan data collected during these surveys J2-95-MB, J6-95-MB, M2-95-MB, M1-96-MB, J3-97-MB, and J3-98-MB (<http://walrus.wr.usgs.gov/infobank>).

    Images BSCATyy.TIF for yy = 10s, 11s, and 12 through 22 have 5-m pixel resolution with pixel values stretched from processed EM1000 (P1-95-MB) and EM300 (A4-98-MB) data (<http://walrus.wr.usgs.gov/infobank>).

      IMAGE        ROWS COLS  FILESIZE (Mb)
      bscat01.tif  5281 4486	   24
      bscat02.tif  2443 2237	    5
      bscat03.tif  3995 2568	   10
      bscat04.tif  5585 4500	   25
      bscat05.tif  3944 4507	   18
      bscat06.tif  4531 4514	   20
      bscat07.tif  2884 1360	    4
      bscat08.tif  2406 2901	    7
      bscat09.tif  3285 4514	   15
      bscat10n.tif 3306 4522	   15
      bscat11n.tif 3506 2791	    3
      bscat10s.tif 1130 2260	   10
      bscat11s.tif 1105 1321	    1
      bscat12.tif  2795  565	    2
      bscat13.tif  2798 2264	    6
      bscat14.tif  2801  979	    3
      bscat15.tif  2795  565	    2
      bscat16.tif  2798 2267	    6
      bscat17.tif   269  363	    1
      bscat18.tif  2795  566	    2
      bscat19.tif  2798 1443	    4
      bscat20.tif  2795 1583	    4
      bscat21.tif  2797 1526	    4
      bscat22.tif   763 1506	    1
    
    The image boundaries in UTM coordinates are
        IMAGE        XMIN   YMIN     XMAX   YMAX
      bscat01.tif   555519 4095055  566734 4108258
      bscat02.tif   566623 4095136  572216 4101243
      bscat03.tif   560422 4085148  566842 4095136
      bscat04.tif   566733 4081268  577983 4095231
      bscat05.tif   577855 4081363  589123 4091223
      bscat06.tif   588977 4081472  600262 4092800
      bscat07.tif   600100 4081596  603500 4088806
      bscat08.tif   570857 4075349  578110 4081364
      bscat09.tif   577983 4073261  589268 4081473
      bscat10n.tif  589122 4073330  600427 4081595
      bscat11n.tif  600263 4072970  607241 4081735
      bscat10s.tif  589125 4067604  600425 4073254
      bscat11s.tif  600265 4067729  606870 4073254
      bscat12.tif   586590 4053629  589415 4067604
      bscat13.tif   589270 4053739  600590 4067729
      bscat14.tif   600425 4053864  605320 4067869
      bscat15.tif   586730 4039764  589555 4053739
      bscat16.tif   589415 4039874  600750 4053864
      bscat17.tif   600590 4052659  602405 4054004
      bscat18.tif   586870 4025899  589700 4039874
      bscat19.tif   589555 4026009  596770 4039999
      bscat20.tif   581930 4012034  589845 4026009
      bscat21.tif   589700 4012144  597330 4026129
      bscat22.tif   589845 4008449  597375 4012264
    
    Polygon coverage QUAD75 consists of the outlines for 7.5-minute quadrangles by which the backscatter images are numbered. Its attributes are:

     QUAD - quadrangle number 1 through 22
     NAME - informal quadrangle names adapted from standard
             7.5-minute topographic quadrangle names
         1 Ano Nuevo
         2 Davenport
         3 Santa Cruz W2
         4 Santa Cruz W1
         5 Santa Cruz
         6 Soquel
         7 Watsonville W
         8 Moss Landing W3
         9 Moss Landing W2
        10 Moss Landing W1
        11 Moss Landing
        12 Marina W2
        13 Marina W1
        14 Marina
        15 Monterey W
        16 Monterey
        17 Seaside
        18 Soberanes Point W
        19 Soberanes Point
        20 Point Sur W
        21 Point Sur
        22 Pfieffer Point W
    
    Entity_and_Attribute_Detail_Citation: none


Who produced the data set?

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

  2. Who also contributed to the data set?

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

    Florence L. Wong
    United States Geological Survey (USGS)
    Geologist, GIS Coordinator
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5327 (voice)
    (650) 329-5190 (FAX)
    fwong@usgs.gov


Why was the data set created?

These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information about the shallower areas of the Monterey Bay National Marine Sanctuary.


How was the data set created?

  1. From what previous works were the data drawn?

    Chavez and others, 1998 (source 1 of 3)
    P.S. Chavez, Jr., Isbrecht, J., Gabel, G., Galanis, P., Ross, S., Anima, R., and Eittreim, S., 1998, Seafloor image map of the Monterey Bay region.

    Online Links:

    Type_of_Source_Media: electronic
    Source_Contribution: explanation of methods, Klein, EM1000 data

    Eittreim and others, 1998 (source 2 of 3)
    Eittreim, S.L., Stevenson, A.J., and Maher, N., 1998, Seafloor sidescan sonar image files as 5-m grids.

    Type_of_Source_Media: electronic file
    Source_Contribution: EM300 sidescan sonar data

    Chavez and others, 2001 (source 3 of 3)
    Chavez, P.S., Jr., Isbrecht, J., Galanis, P., Gabel, G.L., Sides, S.C., Soltesz, D.L., Ross, S.L., and Velasco, M.G., 2001, Processing, mosaicking and management the Monterey Bay digital side-scan sonar images.: Marine Geology xx.

    Type_of_Source_Media: paper
    Source_Contribution: description of image processing

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

    Date: 30-Sep-1998 (process 1 of 6)
    Klein sidescan sonar data. USGS Coastal and Marine Geology (CMG) image processing group completed 1-meter mosaic of sidescan sonar image for survey area between Point Ano Nuevo and Monterey Canyon. CMG processing blocks were numbered 1 through 13. CMG filename mbay_mosaic_blk01_blk13_1m.

    Date: Jun-2000 (process 2 of 6)
    Converted Klein 1-meter mosaic from raw format (.BIL) to ArcInfo grid. Cell values of 0 include NODATA. Extracted polygon coverage of zero-value cells or cell clusters. Modified coverage to retain truly NODATA polygons; converted polygon coverage to grid mask. Applied NODATA mask to mosaic grid to redefine cells with 0 where there is no data to NODATA, leaving other 0 cells unchanged. Added 1 to value of grid so that lowest pixel value is 1. Remapped range of sidescan grid values for better contrast.

    Date: Mar-1998 (process 3 of 6)

    EM1000 sidescan data from inner shelf between Moss Landing and Monterey. Image (.BIL) files with 2.5-m pixels for north half and south half downloaded from CMG image processing group. Converted images to ArcInfo grids. Re-projected coordinates from Mercator projection to UTM. Combined north and south grids into one.

    Date: Oct-2000 (process 4 of 6)

    EM300 sidescan data south of Monterey Canyon and west of location of EM1000 data provided as 5-m ArcInfo grids by Norman Maher (MBARI).

    Date: Feb-2000 to 200012 (process 5 of 6)

    Merged all grids of sonar image and subdivided them into 7.5-minute quadrangles. Cell size north of Monterey Canyon is 2.5 m; south of Monterey Canyon is 5 m. Converted grids to TIFF images.

    Date: 13-Feb-2001 (process 6 of 6)
    First draft of metadata created by F.L. Wong using a modified version of FGDCMETA.AML on ARC/INFO data set BSCATxx.TIF

  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?

    Sidescan sonar images are discontinuous where survey tracklines were not run.

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

    Not applicable for raster data.


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:
Please recognize the U.S. Geological Survey (USGS) as the source of this information.

Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.

The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

This information is not intended for navigational purposes.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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

    United States Geological Survey (USGS)
    c/o Florence L. Wong
    Geologist, GIS Coordinator
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5327 (voice)
    (650) 329-5190 (FAX)
    fwong@usgs.gov

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

    USGS Open-File Report 01-179

  3. What legal disclaimers am I supposed to read?

    Please recognize the U.S. Geological Survey (USGS) as the source of this information.

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.

    Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

    The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 27-Mar-2001
Last Reviewed: May-2001

Metadata author:
United States Geological Survey (USGS)
c/o Florence L. Wong
Geologist, GIS Coordinator
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5327 (voice)
(650) 329-5190 (FAX)
fwong@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata ("CSDGM version 2") (FGDC-STD-001-1998)


http://geopubs.wr.usgs.gov/open-file/of01-179/data/backscat/bscat_faq.html
Maintained by: Florence L. Wong
Last modified: Jul 2, 2001 (flw)
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