GPS NAVIGATION: Text Files of the GPS Navigation Logged with an ASHTECH G12 Sensor During OSV Bold Cruise 2010-015-FA of May 24 to May 28, 2010

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

Frequently-anticipated questions:

What does this data set describe?

Title:
GPS NAVIGATION: Text Files of the GPS Navigation Logged with an ASHTECH G12 Sensor During OSV Bold Cruise 2010-015-FA of May 24 to May 28, 2010
Abstract:
The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During October 2008 NOAA completed hydrographic survey H11997 offshore in eastern Long Island Sound, and during May 2010 bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Two interpretive data layers were derived from the multibeam echo-sounder and the ground-truth data used to verify them. For more information on the ground-truth survey see <http://quashnet.er.usgs.gov/data/2010/10015/>
  1. How should this data set be cited?

    Poppe, Larr, 2011, GPS NAVIGATION: Text Files of the GPS Navigation Logged with an ASHTECH G12 Sensor During OSV Bold Cruise 2010-015-FA of May 24 to May 28, 2010: Open-File Report 2010-1150, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Poppe, L.J., McMullen, K.Y., Ackerman, S.D., Blackwood, D.S., Schaer, J.D., Forrest, M.R., Ostapenko, A.J., and Doran, E.F., 2011, Sea-Floor Geology and Topography Offshore in Eastern Long Island Sound: Open-File Report 2010-1150, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -72.402855
    East_Bounding_Coordinate: -72.152318
    North_Bounding_Coordinate: 41.287199
    South_Bounding_Coordinate: 41.109415

  3. What does it look like?

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

    Beginning_Date: 24-May-2010
    Ending_Date: 28-May-2010
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: text file

  6. How does the data set represent geographic features?

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

      This is a Point data set.

    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 D_WGS_1984.
      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?

    Entity_and_Attribute_Overview:
    Global Positioning System Fix Data
    GGA Strings are in comma-delimited ASCII text and each record is in the format: $GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh
    Where the fields represent: 1 = UTC of Position 2 = Latitude (degrees decimal minutes) 3 = N or S 4 = Longitude (degrees decimal minutes) 5 = E or W 6 = GPS quality indicator (0=invalid; 1=GPS fix; 2=Diff. GPS fix) 7 = Number of satellites in use [not those in view] 8 = Horizontal dilution of position 9 = Antenna altitude above/below mean sea level (geoid) 10 = Meters (Antenna height unit) 11 = Geoidal separation (Diff. between WGS-84 earth ellipsoid and mean sea level. -=geoid is below WGS-84 ellipsoid) 12 = Meters (Units of geoidal separation) 13 = Age in seconds since last update from diff. reference station 14 = Diff. reference station ID# 15 = Checksum
    For the GPVTG strings: VTG=actual track made good and speed over ground $GPVTG,t,T,m,M,s.ss,N,s.ss,K*hh 1=True course made good over ground, degrees 2=Fixed text 'T' indicates that track made good is relative to true north 3=Magnetic course made good over ground, degrees 4= Fixed text 'M' indicates that track made good is relative to magnetic north 5=Speed over ground in knots 6=Fixed text 'N' indicates that speed over ground in knots 7=Speed over ground in kilometers/hour 8=Fixed text 'K' indicates that speed over ground is in kilometers/hour 9=Checksum.
    Entity_and_Attribute_Detail_Citation:
    The definitions of the GGA strings were acquired from: <http://www.marimsys.com/pages/nmea_codes.htm>

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?

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

    (508) 548-8700 x2314 (voice)
    5084572310 (FAX)

Why was the data set created?

The purpose of these data is to provide the navigation for OSV Bold cruise 2010-015-FA as recorded from an Ashtech G12 Global Positioning System (GPS) Sensor. This provides an archive of the original navigation as well as allowing others to reprocess the navigation for their purposes.

How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: 2010 (process 1 of 1)
    A USB thumb drive was used to transfer the text navigation files from the computer receiving the GPS string from the ASHTECH G12 Sensor. The original navigation files are stored in a single folder. The filenames are in the format of cruiseid_julianday.txt. The times in the files reflect UTC (Coordinate Universal Time) times.

    Person who carried out this activity:

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

    (508) 548-8700 x2314 (voice)
    5084572310 (FAX)

    Data sources produced in this process:
    • 2010_015_jd144nav.txt
    • 2010_015_jd145nav.txt
    • 2010_015_jd146nav.txt
    • 2010_015_jd147nav.txt
    • 2010_015_jd148nav.txt

  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?

    The navigation receiver used was an Ashtech. The accuracy of this system is better than 7 meters.

  3. How accurate are the heights or depths?

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

    These files represent all the navigation recorded from the Ashtech unit during OSV Bold cruise 2010-015-FA.

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

    These are the original files recorded from the Ashtech navigation unit. No additional checks or corrections have been made to these files.

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:
The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.

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

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

    (508) 548-8700 x2314 (voice)
    5084572310 (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?

    Neither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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 user must have software capable of uncompressing the WinZip file.

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2010
Metadata author:
Larry Poppe
U.S. Geological Survey
Geologist
Woods Hole Coastal and Marine Science Center
Woods Hole, MA 02543-1598

(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)
Metadata extensions used:

Generated by mp version 2.9.6 on Tue Oct 19 14:09:48 2010