Sustainable Seas Expedition Tracklines: Years 2000 and 2001

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Frequently-anticipated questions:

What does this data set describe?

Title: Sustainable Seas Expedition Tracklines: Years 2000 and 2001
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?

    Halley, Robert B. , Twichell, David C. , and Cross, VeeAnn A. , 2005, Sustainable Seas Expedition Tracklines: Years 2000 and 2001:.

    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: -83.928788
    East_Bounding_Coordinate: -83.630502
    North_Bounding_Coordinate: 26.027587
    South_Bounding_Coordinate: 24.703923

  3. What does it look like?

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

    Calendar_Date: 26-Aug-2000
    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):

      • String (12)

    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.

    Internal number automatically generated. (Source: Software created.)


    Unique ID identifying the SSE dive. (Source: Scientist.)

    Character set.

    Submarine used on the dive. (Source: Scientist.)

    Character set.

    Start date and time of the dive. (Source: Scientist.)

    Character set representing month/day/year and hour:min:sec.

    End date and time of the dive. (Source: Scientist.)

    Character set representing month/day/year and hour:min:sec.

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?

    Robert B. Halley
    U.S. Geological Survey
    USGS Center for Coastal and Watershed Studies
    St. Petersburg, FL 33701-4846

    (727) 803-8747 x3113 (voice)
    (727) 803-2032 (FAX)

Why was the data set created?

This polyline shapefile was generated to indicate the location of the Sustainable Seas Expedition dives in the Pulley Ridge area aboard the NOAA ship Gordon Gunter.

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 8)
    Converted the SSE navigation from excel spreadsheets to individual point shapefiles for each dive. This was accomplished by exporting the necessary records to a text file and then loading those as an event theme into ArcView and saving as a shapefile.

    (process 2 of 8)
    A line shapefile was then generated connecting the points in the order of navigation acquisition. This was done to help more readily spot obvious outliers.

    (process 3 of 8)
    In some cases, running a filter over the points helped remove outliers. (This is discussed in the next process step.) Some files had major outliers that needed to be deleted prior to the more automated filter process. This was done by visual inspection and usually just involved a few points. This modified shapefile was saved under a new name.

    (process 4 of 8)
    The submarine typically travels very slowly to aid in seafloor observations. In fact, the submarine can't travel extremely fast. Because of this, I was able to write a filter that looked at distance traveled between each navigation point. I could vary the filter values and see which points were selected as acceptable based on the filter values. The visual inspection of what appeared sensible determined if the filter values were accepted.

    (process 5 of 8)
    Once a reasonable filter was applied, those selected points were then saved into a new shapefile with the filter values used added as an attribute to the file. The filter works such that the first number is the distance accepted as movement between 2 adjacent points in time. The second number is the increment added to each subsequent time step. This value is smaller than the first otherwise before long very large error values would be accepted.

    (process 6 of 8)
    Once the individual dives were processed, these files were then combined into one shapefile using the Geoprocessing wizard in ArcView 3.2a.

    (process 7 of 8)
    An in-house avenue script (navpnts2lines.ave) was used to convert the point shapefile to a polyline shapefile based on the "sse_id" attribute.

    (process 8 of 8)
    The "end_time" attribute was added to the shapefile.

  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 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 13:22:59 2005