2011_006GPSNAV: Text Files of the DGPS Navigation Logged with HYPACK Software on U.S. Geological Survey (USGS) Cruise 2011-006-FA from June 13 to June 21, 2011

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Frequently-anticipated questions:

What does this data set describe?

Title:
2011_006GPSNAV: Text Files of the DGPS Navigation Logged with HYPACK Software on U.S. Geological Survey (USGS) Cruise 2011-006-FA from June 13 to June 21, 2011
Abstract:
The USGS, in cooperation with NOAA, is producing detailed maps of the seafloor off southern New England. The current phase of this cooperative research program is directed toward analyzing how bathymetric relief relates to the distribution of sedimentary environments and benthic communities. As part of this program, digital terrain models (DTMs) from bathymetry collected as part of NOAA's hydrographic charting activities are converted into ESRI raster grids and imagery, verified with bottom sampling and photography, and used to produce interpretations of seabed geology and hydrodynamic processes. Although each of the 7 continuous-coverage, completed surveys individually provides important benthic environmental information, many applications require a geographically broader perspective. For example, the usefulness of individual surveys is limited for the planning and construction of cross-Sound infrastructure, such as cables and pipelines, or for the testing of regional circulation models. To address this need, we integrated the 7 contiguous multibeam bathymetric DTMs into one dataset that covers much of Block Island Sound. The new dataset is adjusted to mean lower low water, is provided in UTM Zone 19 NAD83 and geographic WGS84 projections, and is gridded to 4-m resolution. This resolution is adequate for seafloor-feature and process interpretation, but small enough to be queried and manipulated with standard GIS programs and to allow for future growth. Natural features visible in the grid include boulder lag deposits of submerged moraines, sand-wave fields, and scour depressions that reflect the strength of the oscillating tidal currents. Bedform asymmetry allows interpretations of net sediment transport. Together the merged data reveal a larger, more continuous perspective of bathymetric topography than previously available, providing a fundamental framework for research and resource management activities off this portion of the Rhode Island coast. For more information on the ground-truth surveys see <http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-006-FA>
  1. How should this data set be cited?

    Poppe, Larry, 2012, 2011_006GPSNAV: Text Files of the DGPS Navigation Logged with HYPACK Software on U.S. Geological Survey (USGS) Cruise 2011-006-FA from June 13 to June 21, 2011: Open-File Report 2012-1005, 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., Danforth, W.W., McMullen, K.Y., Blankenship, M.A., Glomb, K.A., Wright, D.B., and Smith, S.M., 2012, Sea-Floor Character and Sedimentary Processes of Block Island Sound, Offshore Rhode Island: Open-File Report 2012-1005, 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: -71.852
    East_Bounding_Coordinate: -70.230258
    North_Bounding_Coordinate: 41.46
    South_Bounding_Coordinate: 41.121169

  3. What does it look like?

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

    Beginning_Date: 13-Jun-2011
    Ending_Date: 21-Jun-2011
    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:
    The times recorded in the navigation file are in UTC. Keywords and the information they provide are as follows: FTP: The first record located at the top of the header used to identify the file format. VER: HYPACK version number. INF: General survey information filled in by the data technician.
    ELL: Ellipsoid information. The name of the ellipsoid followed by the semi-major axis in meters and the flattening ration. PRO: Project information record where TME indicates Transverse Mercator and the central meridian of -69 indicates UTM, zone 19. DTM: Datum transformation record. GEO: Geoid Model File. Blank if not present. GEO <geo_file> <h_corr> where 'h_corr' is orthometric height correction in meters. HVU: Horizontal and Vertical Units (meters) TND: Survey time and date in UTC. DEV 0: Lines with device designation 0 are lines of DGPS data. OFF 0: device offsets for device 0. Format of the value is OFF dn n1 n2 n3 n4 n5 n6 n7 where dn=device number; n1=starboard, port offsets where positive is starboard; n2=forward, aft offset where positive is forward; n3=height (antenna) or depth (transducer draft) offset - always positive; n4=yaw rotation angle where positive for clockwise rotation; n5=roll rotation angle where port side up is positive; n6=pitch rotation angle where bow up is positive; n7=device latency in seconds. No offset for device 0 during this data collection. DEV 1: Disabled. DEV 2: Disabled. DEV 3: Indicates that the lines with device designation 3 are lines of bathy data. OFF 3: Offset of bathy data (transducer located 0.6 m below water line of vessel). EOH: end of header The remaining elements have similar information in the first 3 columns. The first column will indicate the data type, the second column will indicate the device that recorded the information and the third column is the time tag (seconds past midnight) that is also sometimes referred to as the latency. The remaining information on each line is specific to the data type. POS: Position of the ship - in this case the antenna location - in the format "POS dn t x y" where dn=device number; t=time tag (seconds past midnight); x=easting; y=northing. On this cruise these values are in UTM, Zone 19, WGS84. EC1: Echo Sounding (single frequency) in the format "EC1 dn t rd" where dn=device number; t=time tag (seconds past midnight); rd=raw depth.
    GYR: Gyro Data (heading) in the format "GYR dn t h" where dn=device number; t=time tag (seconds past midnight); h=ship heading angle. MSG: Message string in the format "MSG dn t message" where dn=device number; t=time tag (seconds past midnight); message is the message sent from the device. On this cruise, four different messages were sent from the DGPS: $GPVTG, $GPZDA, $SDDPT, and $GPGGA. These will be defined later.
    FIX: Event marked manually by the user in the format "FIX dn t event number where dn=device number; t=time tag (seconds past midnight); event number=event number (1,2,3...) automatically increments. The device number is automatically supplying a value of 99.
    QUA: Position quality information in the format "QUA dn t n m h sat mode" where dn=device number; t=time tag (seconds past midnight); n=number of values to follow; m = 10 minus HDOP (horizontal dilution of precision); h=HDOP; sat=number of satellites; mode=GPS mode (NMEA 0183 standard values) where 2=Differential GPS fix. The next 3 values are the standard deviation of latitude error (meters), longitude error (meters) and semi-major axis of error ellipsis (meters).
    The NMEA strings present in the HYPACK file are the $GPVTG, $GPZDA, $SDDPT, and $GPGGA. These sentences are defined as follows. $GPVTG is track made good and ground speed in the format "$GPVTG, t, T, m, M, n, N, k, K refcheck" where t=true course made good over ground, degrees; T indicates the previous number refers to true course; m=magnetic course made good over ground, dgrees; M indicates the previous number refers to magnetic course; n=ground speed; N indicates the previous number refers to Knots, k=ground speed; K indicates the previous number refers to Kilometers per hour, refcheck= checksum at the end of the string with the first character an *. $GPZDA is UTC Date/Time and local time zone offset in the format "$GPZDA, hhmmss.ss,dd,mm,yyyy, xx, yy checksum" where hhmmss.ss= time in UTC; dd=UTC day; mm=UTC month; yyyy=UTC year; xx=offset to local time zone in hours; yy=offset to local time zone in minutes;checksum ***on this cruise the navigation computer was set to UTC time so the $GPZDA string indicates zero time offset.
    $GPGGA is GPS fix data in the format "$GPGGA, t, lat, lath, long, longh, q, sat, h, a, M, alt, M, t2, refcheck" where t=time in UTC in the format hhmmss.ss; lat=latitude in the format ddmm.mmmmmm; lath= N or S indicating the latitude hemisphere; long=longitude in the format dddmm.mmmmmm; longh=E or W indicating the longitude hemisphere; q=fix quality where 2 is a DGPS fix; sat=number of satellites; h=Horizontal Dilution of Precision (HDOP); a=Antenna altitude above mean sea level (geoid); M= units of antenna altitude in meters; alt=height of geoid above WGS84 ellipsoid; M=units of geoidal height in meters; t2=time since last DGPS update; refcheck=DGPS reference station id and the checksum. $SDDPT is water depth relative to the transducer. Field 1 is the depth in meters. Field 2 is the offset from the transducer: positive - distance from transducer to water line, or negative - distance from transducer to keel. Field 3 (asterisk and subsequent numbers and characters) is the CRC checksum of the NMEA data.
    Entity_and_Attribute_Detail_Citation:
    The definitions of the HYPACK strings were acquired from the HYPACK software manual available from: <http://www.hypack.com/>. The definitions of the NMEA strings were obtained from: <http://home.mira.net/~gnb/gps/nmea.html> and <http://www.actisense.com/Downloads/TechTalk/NMEA%200183/The%20NMEA%200183%20Information%20Sheet.pdf>. . The SDDPT definition was acquired from: <http://www.eye4software.com/products/gpstoolkit/nmea/>.

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 USGS cruise 2011-006-FA as recorded by CSI LGBX Pro Differential Global Positioning System (DGPS) with HYPACK software. 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: 2011 (process 1 of 1)
    A USB thumb drive was used to transfer the text navigation files from the computer running the HYPACK navigation software. The original HYPACK navigation files are stored in a single folder. The filenames are in the format of linenumber_starttime.julianday. Since we weren't surveying any previously loaded lines, the "linenumber" is always 000. An example filename is 000_1214.202 which reflects line 000, start time 1214 and Julian day 202. The times in the filename 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)

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

    Poppe, L.J., McMullen, K.Y., Ackerman, S.D., Schaer, J.D., and Wright, D.B., 2012, Sea-floor character and sedimentary processes in the vicinity of Cross Rip Channel, Nantucket Sound, offshore southeastern Massachusetts: Open-File Report 2011-1222, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    McMullen, K.Y., Poppe, L.J., Ackerman, S.D., Worley, C.R., Nadeau, M.A., and Van Hoy, M.V., 2012, Sea-floor geology in central Rhode Island Sound south of Sakonnet Point, Rhode Island: Open-File Report 2012-1004, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: 1 DVD-ROM

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 a CSI LGBX Pro DGPS2. The accuracy of this system is better than 10 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 by the HYPACK software version 10.0.5.31 during USGS cruise 2011-006-FA.

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

    These are the original files recorded by the HYPACK navigation software. No additional checks or corrections have been made to these files. Also, two navigation devices were recorded. Device 0 recorded DGPS and are the valid fixes.

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: 15-Feb-2012
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 Wed Feb 15 12:58:40 2012