G97_15MNPNT.SHP - 15 minute interval navigation points for the 1997 R/V GYRE (97006) seismic tracklines

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

Frequently-anticipated questions:


What does this data set describe?

Title:
G97_15MNPNT.SHP - 15 minute interval navigation points for the 1997 R/V GYRE (97006) seismic tracklines
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?

    Cross, VeeAnn, 2005, G97_15MNPNT.SHP - 15 minute interval navigation points for the 1997 R/V GYRE (97006) seismic tracklines: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Twichell, D.C, Cross, V.A., 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:

    Other_Citation_Details: 1 DVD-ROM

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -92.778955
    East_Bounding_Coordinate: -91.995983
    North_Bounding_Coordinate: 27.246257
    South_Bounding_Coordinate: 26.449550

  3. What does it look like?

    <http://pubs.usgs.gov/of/2005/1071/data/seismic/1997/nav/g97_15mnpnts.gif> (GIF)
    Browse image showing overview of data extent and coverage.
    <http://pubs.usgs.gov/of/2005/1071/data/seismic/1997/nav/g97_15mnpnts-thumb.gif> (GIF)
    Thumbnail image showing overview of data extent and coverage.

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

    Beginning_Date: 09-Apr-1997
    Ending_Date: 13-Apr-1997
    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 (367)

    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?

    g97_15mnpnt
    Feature geometry (Source: ESRI)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    LONGITUDE
    longitude coordinate, in decimal degrees, of navigation fix (Source: user defined)

    Range of values
    Minimum:-92.778955
    Maximum:-91.995983
    Units:decimal degrees
    Resolution:.000001

    LATITUDE
    latitude coordinate, in decimal degrees, of navigation fix (Source: User defined)

    Range of values
    Minimum:26.449550
    Maximum:27.246257
    Units:decimal degrees
    Resolution:.000001

    JDTIME
    Date and time recorded as Julian day: Hour: Minute: Second (Source: User defined)

    Character string - JDAY:hh:mm:ss

    LINE
    Line number for seismic profile (Source: User defined)

    Character string - line identifier


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?

    VeeAnn Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x 2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov


Why was the data set created?

This GIS shapefile shows points at a fifteen minute interval along the tracklines on which single-channel seismic-reflection profiles were collected in 1997 aboard the R/V GYRE. The seismic data have been published in SEG-Y format by Nealon and others (2000). Each point has the Julian day, time, and line number associated with it. The seismic profiles are annotated with time, so this shapefile can be used to correlate features on the seismic profiles with the tracklines


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 3)
    GPS navigation was logged at a 10 second interval to a PC.

    Data sources used in this process:

    • GPS receiver

    Data sources produced in this process:

    • nav1.raw
    • nav2.raw
    • nav3.raw
    • nav4.raw
    • nav5.raw

    (process 2 of 3)
    The time, latitude, and longitude fields were extracted from the raw data files and written to a text file. Fixes at a 1-minute interval were extracted from this file and then further edited to include only the intervals of time when seismic data were being collected. This file then was further subsampled to a 15-minute interval. The resulting file was imported to ArcView and converted to a shapefile, which provides a point every minute along the survey tracklines.

    Person who carried out this activity:

    VeeAnn Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x 2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Data sources used in this process:
    • nav1.raw
    • nav2.raw
    • nav3.raw
    • nav4.raw
    • nav5.raw

    Data sources produced in this process:

    • nav_15mnpnt.shp

    Date: 2005 (process 3 of 3)
    Renamed g97_15mnpnt.shp

    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:
    • nav_15mnpnt.shp

    Data sources produced in this process:

    • g97_15mnpnt.shp

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

    Nealon, J.W., Dillon, W.P., and Twichell, D.C., 2000, Seismic reflection results of the GYRE 1997 cruise at the Bryant Canyon of the Louisiana Gulf Coast: Open-File Report 99-449, U.S. Geological Survey, Reston, VA.

    Online Links:


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?

    Navigation data were collected using both Differential GPS and P-CODE GPS receivers. The GI Airgun was towed 10 m aft of the ship. The two-channel streamer was towed approximately 100 m aft of the ship, and each channel was 25 m long.

  3. How accurate are the heights or depths?

    The airgun was towed at a depth of approximately 1 meter. The streamer was towed at a depth of approximately 5 m. There was no correction to a datum such as mean sea level.

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

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

    No additional checks for topological consistency were performed on this data set. No duplicate features are present.


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)

    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

  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?

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

    The data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS® or ArcView® 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing data. A free data viewer, arcexplorer, capable of displaying the data is available from ESRI at www.esri.com.


Who wrote the metadata?

Dates:
Last modified: 12-Dec-2005
Metadata author:
David Twichell
U.S. Geological Survey
Oceanographer
384 Woods Hole Road
Woods Hole, MA 02543-1598
USA

508-458-8700 x2266 (voice)
508-457-2310 (FAX)
dtwichell@usgs.gov

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


Generated by mp version 2.8.6 on Mon Dec 12 14:45:49 2005