DH_HYPACK_NAV: Text files of the navigation logged with HYPACK Software during surveys 06012 and 07001 conducted by the U.S. Geological Survey offshore of Massachusetts between Duxbury and Hull.

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

Frequently-anticipated questions:

What does this data set describe?

Title:
DH_HYPACK_NAV: Text files of the navigation logged with HYPACK Software during surveys 06012 and 07001 conducted by the U.S. Geological Survey offshore of Massachusetts between Duxbury and Hull.
Abstract:
These data were collected under a cooperative agreement with the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, Woods Hole Science Center (WHSC). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of sea-floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters (5-30 m deep) of Massachusetts between the New Hampshire border and Cape Cod Bay. Data collected for the mapping cooperative have been released in a series of USGS Open-File Reports (<http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html>). This spatial dataset is from the study area located between Duxbury and Hull Massachusetts, and consists of high-resolution geophysics (bathymetry, backscatter intensity, and seismic reflection) and ground validation (sediment samples, video tracklines and bottom photographs). The data were collected during four separate surveys conducted between 2003 and 2007 (NOAA survey H10993 in 2003, USGS-WHSC survey 06012 in 2006, and USGS-WHSC surveys 07001 and 07003 in 2007) and cover more than 200 square kilometers of the inner continental shelf.
  1. How should this data set be cited?

    U.S. Geological Survey, 2010, DH_HYPACK_NAV: Text files of the navigation logged with HYPACK Software during surveys 06012 and 07001 conducted by the U.S. Geological Survey offshore of Massachusetts between Duxbury and Hull.: Open-File Report 2009-1072, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Barnhardt, Walter A. , Ackerman, Seth D. , Andrews, Brian D. , and Baldwin, Wayne E. , 2010, Geophysical and Sampling Data from the Inner Continental Shelf: Duxbury to Hull, Massachusetts.: Open-File Report 2009-1072, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, Massachusetts.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.828007
    East_Bounding_Coordinate: -70.404034
    North_Bounding_Coordinate: 42.340049
    South_Bounding_Coordinate: 41.935706

  3. What does it look like?

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

    Beginning_Date: 04-Aug-2006; 20070422
    Ending_Date: 20-Aug-2006; 20070502
    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 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:

    INF: General survey information filled in by the data technician. This typically contains the survey participants, the vessel name, other agencies involved with the survey, and the location of the survey.

    FIL: Raw format file.

    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. Blank if not present.

    HVU: Horizontal and Vertical Units (meters)

    TND: Survey time and date in UTC.

    DEV 0: For surveys 06012 and 07001: Indicates that lines collected with device designation 1 are using Ashtech Z-Extreme, capable of recording antenna elevations above a vertical datum (i.e. real-time kinematic, RTK).

    OFF: device offsets

    DEV 1: For surveys 06012 and 07001: Indicates that the lines with device designation 1 are lines of Ashtech DGPS data - which was disabled for parts of these surveys.

    PRD: Private Device Data (multiple formats depending on the type of device generating the data).

    DEV 2: For survey 06012-leg1: Indicates that the lines with device designation 2 are lines of the motion reference unit. For surveys 06012-leg2 and 07001: Indicates that the lines with device designation 2 are lines of the single-beam echosounder.

    DEV 3: For survey 06012-leg1: Indicates that the lines with device designation 3 are lines of the single-beam echosounder.

    LIN 2: planned line data follows

    PTS: planned line waypoints (easting and northing, UTM, zone 19N, meters)

    LBP: planned line begin point (easting and northing, UTM zone 19N, meters)

    LNN: planned line name

    EOL: end of planned line

    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 (0 for Ashtech) 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. Not all data types were recorded in each HYPACK file.

    POS: Position of the ship 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.

    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.

    RAW: Position information in the format "RAW dn t n lat long alt utc" where dn=device number; t=time tag (seconds past midnight); n=number of values to follow; lat=raw latitude X 100; long=raw longitude X 100; alt=antenna altitude above ellipsoid (meters); utc=GPS time in the format HHMM.

    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. During surveys 06012 and 07001 there were several different messages were sent from the GPS systems: $GPGGA, $GPVTG, and $GPZDA (06012 also had $GPHDT and 06012-leg2 had $PASHR,POS and $PASHR,SAT). These will be defined later.

    TID: Tide correction in the format "TID dn t dc" where dn=device number, t=time tag (seconds past midnight), dc = draft correction.

    EC1: Echo sounding (singe 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=heading.

    FIX: Fix (event) mark in the format "FIX vn" where n=FIX format version number.

    The (National Marine Electronics Association) NMEA strings $GPGGA, $GPVTG, $GPZDA, $GPHDT are stored in the HYPACK file. These are defined as follows.

    $GPGGA is GPS fix data in the format "$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 hemisphere; q=fix quality where 0=fix not available or invalid; 1=GPS fix; 2=Differential GPS fix; 3=GPS PPS Mode fix; 4=RTK fix; 5=RTK float; 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.

    Example: $GPGGA,173356.00,4204.848996,N,07036.929067,W,4,09,01.1,00003.278,M,-028.888,M,01,0000*56 UTC Time = 173356 Latitude = 4204.848996 N Longitude = 7036.929067 W Fix Quality = 4 (indicates RTK) Number of satellites = 9 HDOP = 01.1 relative accuracy of horizontal position Altitude = 3.278 meters above mean sea level Height of geoid above WGS84 ellipsoid = -28.888 meters Time since last update = 01 Checksum = *57.

    $GPVTG is track made good and ground speed in the format "$GPVTG, true, T, mag, M, grsp1, N, grsp2, K, mode", where t=true course made good over ground in degrees, T= True, m=magnetic course made good over ground in degrees, M=magnetic, grsp1=ground speed, N=Knots, grsp2=ground speed, K=Kilometers per hour, mode=Mode indicator (A=Autonomous, D=Differential, E=Estimated, N=Data not valid).

    Example: $GPVTG,340.39,T,356.37,M,005.50,N,010.18,K,D*27 True course made good: 340.39 Magnetic course made good: 356.37 Ground speed (knots) = 5.5 Ground speed (kilometers) = 10.18 Mode=Differential

    $GPZDA is UTC Date/Time and Local Time Zone Offset in the format "$GPZDA,hhmmss.ss,xx,xx,xxxx,xx,xx" where hhmmss.ss=UTC, xx=Day, 01 to 31, xx=month, 01 to 12, xxx=Year, xx=Local zone description, 00 to +/- 13 hours, xx=Local zone minutes description (same sign as hours), checksum.

    Example: $GPZDA,173357.00,28,04,2007,,*69 UTC= 173357.00 UTC day = 28 UTC month = 04 UTM year = 2007 Local zone hours = null Local zone minutes = null Checksum = *69

    $GPHDT is Actual vessel heading in degrees in format "$GPHDT,xxx.x,T" where xxx.x=heading in degrees and T indicates True Heading, checksum

    Example: $GPHDT,005.533,T*35 Heading in Degrees = 5.533 True = T Checksum = *35

    $PASHR,POS is Position information and $PASHR,SAT is GPS satellite tracking status information. Both are Ashtech proprietary format; no additional explanation could be found.

    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.nps.gov/gis/gps/NMEA_sentences.html>

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?

    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov

Why was the data set created?

To provide all of the navigation data files acquired during USGS surveys 06012 and 07001 offshore of Massachusetts, between Duxbury and Hull. Survey 06012 was conducted aboard the R/V Megan Miller August 4-20, 2006 and survey 07001 was conducted aboard the R/V Rafael April 22 - May 2, 2007. HYPACK software was used to log these navigation data.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    Real-Time Kinematic (RTK) navigation data were collected using an Ashtech Z-Extreme receiver. An RTK antenna was positioned between the forward and aft Differential Global Positioning System (DGPS) antennas used by the Coda Octopus F180R motion reference unit (MRU) for position and heading. The three antennas are mounted on a rigid horizontal pole that is 6.76 meters directly above the MRU and swath bathymetric transducers; an integral part of the sidemount used to deploy the swath bathymetric system from the starboard side of the R/V Megan Miller. The RTK antenna location was defined within HYPACK.

    Raw navigation data were saved in HYPACK format (<http://www.hypack.com>). File name convention is LLL_TTTT.DDD, where LLL is the HYPACK line number, TTTT is the 24 hour time for the beginning of the file, and DDD is the Julian day. Times were recorded in UTC (Coordinate Universal Time).

    The GPS navigation was significantly hindered by interference during the first leg of survey 06012 (lines l1f1 - l99f2, 4-14 Aug 2006). Frequent navigation dropouts halted data collection for extended periods during the survey.

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

    Date: Aug-2006; 200705 (process 1 of 1)
    During survey 06012: Raw HYPACK navigation files were transferred from the navigation acquisition computer to a Macintosh RAID server for accessibility and archival. During survey 07001: Raw HYPACK navigation files were stored to an external hard-drive on the acquisition vessel and transferred at the end of each survey day to the Macintosh RAID server at the satellite processing office.

    The raw HYPACK navigation files are stored in separate directories indicating the acquisition Julian Day. The filenames in each folder are in the format of linenumber_starttime.julianday. For example, filename 014_1444.113 represents HYPACK line number 014, start time 1444 and Julian Day 113. Times are recorded in UTC (Coordinate Universal Time).

    Person who carried out this activity:

    Science party of surveys 06012 and 07001
    U.S. Geological Survey
    Geologists
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2315 (voice)
    (508) 457-2310 (FAX)
    sackerman@usgs.gov

    Data sources produced in this process:
    • HYPACK navigation files

  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?

    Real-Time Kinematic (RTK) data were collected for both surveys using an Ashtech Z-Extreme receiver and were processed and recorded using navigation software from HYPACK, Inc (<http://www.hypack.com>). These data were incorporated into the geophysical data during acquisition and logged to these HYPACK files in the event that post-processing the horizontal positional information was necessary. RTK provides accuracies on the order of 10s of centimeters (<http://www.navcen.uscg.gov/>).

  3. How accurate are the heights or depths?

    Real-Time Kinematic (RTK) data were collected for both surveys using an Ashtech Z-Extreme receiver and were processed and recorded using navigation software from HYPACK, Inc (<http://www.hypack.com>). These data were incorporated into the geophysical data during acquisition and logged to these HYPACK files for post-processing the RTK navigation to provide improved vertical accuracy for the swath bathymetric data during post-cruise processing. RTK provides accuracies on the order of 10s of centimeters (<http://www.navcen.uscg.gov/>).

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

    These files represent all the navigation recorded by the HYPACK software during USGS surveys 06012 and 07001

  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. Surveying may not have occurred on consecutive days.

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 as the source of this information.

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

    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@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?

    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?

    These data are available as a ASCII text files. To utilize these data, the user must have software capable of viewing text files.

Who wrote the metadata?

Dates:
Last modified: 26-Oct-2009
Metadata author:
Seth Ackerman
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
USA

508-548-8700 x2315 (voice)
508-457-2310 (FAX)
sackerman@usgs.gov

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

Generated by mp version 2.8.25 on Fri Feb 19 21:43:36 2010