Point Shapefile of Bottom Photographs Acquired on Cruise SUN03002

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Frequently-anticipated questions:

What does this data set describe?

Point Shapefile of Bottom Photographs Acquired on Cruise SUN03002
Pulley Ridge is a series of drowned barrier islands that extends almost 200 km in 60-100 m water depths. This drowned ridge is located on the Florida Platform in the southeastern Gulf of Mexico about 250 km west of Cape Sable, Florida. This barrier island chain formed during the initial stage of the Holocene marine transgression. These islands were then submerged and left abandoned near the outer edge of the Florida Platform. The southern portion of Pulley Ridge hosts zooxanthellate scleractinian corals, green, red and brown macro algae, and a mix of deep and typically shallow-water tropical fishes. This reef community is in unusually deep water, and its extent and the controls on its distribution were unknown. To address these questions scientists from the U.S. Geological Survey Coastal and Marine Geology Program in cooperation with scientists from the University of South Florida Department of Marine Sciences have completed a detailed mapping of the southernmost 35 km of Pulley Ridge. The area was mapped using multibeam bathymetry, sidescan-sonar imagery, and high-resolution seismic-reflection profiling to define the geologic framework on which the reef is established. Submersible dives, remotely operated vehicle (ROV) transects, and transects of bottom photographs and video were collected to identify the corals and to map their distribution. This extensive suite of data has been compiled and preliminary analysis of the data suggests that the reefs are not tied to the ridge system, but instead are more broadly distributed. Whether reef distribution is controlled by oceanographic conditions or by subtle differences in the substrate that overlies the barrier island system is unclear, and are topics of continued research.
  1. How should this data set be cited?

    Twichell, David C. , Blackwood, Dann, and Halley, Robert B. , 2005, Point Shapefile of Bottom Photographs Acquired on Cruise SUN03002:.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , Twichell, David C. , Halley, Robert B. , Ciembronowicz, Kate T. , Jarrett, Bret D. , Hammar-Klose, Erika S. , Hine, Al C. , Locker, Stan D. , and Naar, Dave F. , 2005, GIS Compilation of Data Collected from the Pulley Ridge Deep Coral Reef Region: Open-File Report 2005-1089, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -83.742300
    East_Bounding_Coordinate: -83.644173
    North_Bounding_Coordinate: 24.955967
    South_Bounding_Coordinate: 24.699883

  3. What does it look like?

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

    Beginning_Date: 25-Apr-2003
    Ending_Date: 30-Apr-2003
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

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

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity point (1128)

    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 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Film roll number. (Source: Scientist.)

    character set

    CD number that contains the digitized photo. (Source: Digitizing company.)

    Range of values

    Image number for the photo on the CD. (Source: Scientist.)

    Range of values

    Photo number as recorded on the actual photo in the red number code. The numbers are sequential, starting over at 1 for each roll of film. Some numbers are missing because those images were not digitizable. (Source: Technician.)

    Range of values

    Year the photo was acquired. (Source: Scientist.)


    Month the photo was acquired. (Source: Scientist.)


    Day the photo was acquired. (Source: Scientist.)

    Range of values

    Hour the photo was acquired. (Source: Scientist.)

    Range of values

    Minute the photo was acquired. Recorded as a string field. (Source: Scientist.)

    character set

    Dive number referring to the SeaBoss deployment. (Source: Scientist.)

    Range of values

    Longitude of the acquired photo. (Source: Scientist.)

    Range of values
    Units:decimal degrees

    Latitude of the acquired photo. (Source: Scientist.)

    Range of values
    Units:decimal degrees

    Degree of latitude of the acquired photo. (Source: Scientist.)


    Decimal minutes of latitude of the acquired photo. (Source: Scientist.)

    Range of values
    Units:decimal minutes

    Degree of longitude of the acquired photo. (Source: Scientist.)


    Decimal minutes of longitude of the acquired photo. (Source: Scientist.)

    Range of values
    Units:decimal minutes

    Depth of the SeaBoss system based on a pressure transducer mounted to the frame. Values recorded as positive values. (Source: Scientist.)

    Range of values

    Refers to the video tape number that was being recorded when the photo was acquired. (Source: Scientist.)

    character set

    Miscellaneous comments pertaining to the photo. (Source: Scientist.)

    character set

    Unique number assigned to each photo to aid in finding missing information. (Source: Processor.)

    Range of values

    Depth at that point based on the swath bathymetry grid. Values recorded as negative. (Source: Scientist.)

    Range of values

    Variable and pathname indicating the JPEG image that corresponds to the photo acquired at that location. (Source: Processor.)

    character set

    Of note: the CD numbers are not necessarily in order of the photo numbers. For instance, the first part of the first roll of film was placed on CD 2865, while the last part of the last roll of film was placed on CD 2444. Within a roll of film, the CD number increment sequentially. The separated latitude degrees, decimal minutes and longitude degrees and decimal minutes are recorded for the points where navigation came from the video tapes.

    Two depth values exist in the attribute table. One is based on a depth transducer placed on the SeaBOSS system. Because the system is above the seafloor when the image is acquired, this does not reflect water depth - but is probably fairly close. (Attribute: Depth_m_). The other depth attribute (Depth_swat) was derived by extract the grid cell value from the swath bathymetry grid at the point location.

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?

    David C. Twichell
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)

Why was the data set created?

This point shapefile represents the locations of each of the bottom photographs acquired during the SUN00030 cruise. Because the shapefile contains information regarding the JPEG bottom photo, a correlation can be made between the JPEG image and it's location in the study area.

How was the data set created?

  1. From what previous works were the data drawn?

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

    (process 1 of 6)
    Navigation was acquired aboard the boat with a Differential GPS system. This navigation was recorded to a computer, and also as part of the video image. Still photos had a nine digit number recorded on them. The first 3 digits are the image number, the next 2 are the year, the next 2 are the hour, and the final 2 are the minute. The image number recorded on the still photo does not necessarily correspond to the image number given to the digitized image of the photo.

    (process 2 of 6)
    Negatives from the still photos are sent to a place in California to be digitized and written to CD. What is returned is a series of CD's, each with about 100 photos on it. A roll of film might span 3 cd's. The naming convention is as follows: IMG0001.PCD, IMG0002.PCD... Each CD starts with IMG0001, therefore there are duplicate filenames, distinguished only by the CD number.

    (process 3 of 6)
    An excel spreadsheet was created which included the following information for each photo: CD#, Roll#, Image# (as appears on the CD), Photo#, year, month, day, hour, minute, dive #. The hour and minute information (read from the photo) could then be used to merge with the navigation data recorded on computer. Navigation is recorded to the second, yet the time on the photos only goes as far as minute. If one photo was taken in a minute, the navigation time used with 30 seconds after the start of the minute. More than one photo per minute, the following seconds of the minute were used: 2 photos: seconds 15 and 45 3 photos: seconds 15, 30, and 45 4 photos: seconds 10, 20, 30, 40 5 photos: seconds 10, 20, 30, 40, 50 This technique was used on dives 13 and 14. For dives 1-12, navigation was pulled from the video tape based on the presence of the strobe flash associated with a still photo being acquired. This navigation information was entered directly into the excel spreadsheet.

    (process 4 of 6)
    The excel spreadsheet was exported as a comma delimited text file and imported into ArcView 3.2a as a table, and subsequently an event theme. Visual inspection of the data points was used to find outliers and fix the navigation in the excel spreadsheet. Based on the time of the photo, and appropriate navigation fix could be pulled from the computer recorded navigation file. In addition to bad fixes, missing navigation information was fixed in the same manner.

    (process 5 of 6)
    Once the navigation in the excel spreadsheets was fixed, a new comma delimited text file was exported, imported into ArcView 3.2a as a table, added as an event theme and converted to a shapefile.

    (process 6 of 6)
    Additional attribute columns were added and filled.

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

    Cross, VeeAnn A. , Blackwood, Dann S. , Halley, Robert B. , and Twichell, David C. , 2004, Bottom Photographs from the Pulley Ridge Deep Coral Reef: Open-File Report 2004-1228, U.S. Geological Survey, Woods Hole Science Center, Woods Hole, MA.

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 observations, including topology?

How can someone get a copy of the data set?

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

Access_Constraints: None.
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.

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

    David C. Twichell
    U.S. Geological Survey
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    These data were 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 in this report 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 this data, software, or related materials.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 13-May-2005
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Fri May 13 13:35:39 2005