Text files of the Real-time Kinematic (RTK) navigation logged with HYPACK Software during USGS Cruise 07011 conducted off the southern shore of Martha's Vineyard, 2007

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Frequently anticipated questions:


What does this data set describe?

Title:
Text files of the Real-time Kinematic (RTK) navigation logged with HYPACK Software during USGS Cruise 07011 conducted off the southern shore of Martha's Vineyard, 2007
Abstract:
The USGS Woods Hole Science Center conducted a nearshore geophysical survey offshore of the southern coast of Martha's Vineyard, in the vicinity of the Martha's Vineyard Coastal Observatory (MVCO) in August 2007. This mapping program was part of a larger research effort supporting the Office of Naval Research (ONR) Ripples Directed-Research Initiative (DRI) studies at MVCO by providing data collection and modeling. The geophysical data will be used to provide initial conditions for wave and circulation models for the study area. Ultimately, geophysical mapping, oceanographic measurements and modeling will help to improve our understanding of coastal sediment-transport processes.
The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.
  1. How might this data set be cited?
    U.S. Geological Survey, 2009, Text files of the Real-time Kinematic (RTK) navigation logged with HYPACK Software during USGS Cruise 07011 conducted off the southern shore of Martha's Vineyard, 2007: Open-File Report 2008-1288, 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.

    Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.600292
    East_Bounding_Coordinate: -70.511213
    North_Bounding_Coordinate: 41.347370
    South_Bounding_Coordinate: 41.301252
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-Aug-2007
    Ending_Date: 13-Aug-2007
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: online
  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 (Coordinate Universal Time). 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.
    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: Indicated that the lines collected with device designation 0 are lines of single-beam echo sounder.
    OFF: device offsets (none used during this data collection)
    DEV 1: 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 (non used during data collection)
    LIN 2: planned line data follows
    PTS: planned line waypoints (eastings and northings, UTM, zone 19N, meters)
    LBP: planned line begin point (easting and northings, UTM zone 19N, meters)
    LNN 1: 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 (e.g. 1 for Ashtech receiver) 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.
    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.
    EC1: echo sounding (singe frequency). Format "EC1 dn t rd", where dn=device number, t=time tag (seconds past midnight), rd=raw depth.
    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 0=fix not available or invalid; 1=GPS fix; 2=Differential GPS fix; 3=GPS PPS Mode fix; 4=RTK fix; 5=RTK float.
    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.
    TID: Tide correction. Format "dn t dc", where dn=device number, t=time tag (seconds past midnight), dc = draft correction.
    FIX: Fix (event) mark. Format "FIX vn", where n=FIX format version number, Always 2nd record in file.
    The (National Marine Electronics Association) NMEA strings $GPGGA, $GPVTG, and $GPZDA 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,163052.00,4118.964217,N,07036.966471,W,4,10,00.9,00005.332,M,-030.544,M,01,*57 UTC Time = 163052 Latitude = 4118.964217 N Longitude = 7036.966471 W Fix Quality = 4 Number of satellites = 10 HDOP = 00.9 relative accuracy of horizontal position Altitude = 5.332 meters above mean sea level Height of geoid above WGS84 ellipsoid = -30.554 meters Time since last update = 01 Checksum = *57.
    $GPVTG is track made good and ground speed in the format "$GPCTG, true, T, mag, M, grsp, N, grdp, 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, gdsp=ground speed, N=Knots, grsp=ground speed, K=Kilometers per hour, mode=Mode indicator (A=Autonomous, D=Differential, E=Estimated, N=Data not valid).
    Example: $GPVTG,089.23,T,104.82,M,004.86,N,009.02,K,D*28 True course made good: 089.23 Magnetic course made good: 104.82 Ground speed (knots) = 4.86 Ground speed (kilometers) = 9.02 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,163053.00,09,08,2007,,*60 UTC= 163053.00 UTC day = 09 UTC month = 08 UTM year = 2007 Local zone hours = null Local zone minutes = null Checksum = *60
    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

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

Why was the data set created?

These data are supplied to provide the raw navigation collected by an Ashtech Z-Extreme receiver and logged using HYPACK, Inc. navigation software (www.hypack.com). RTK navigation was not incorporated to any of the geophysical systems during data acquisition. These data were stored in order to post-process the RTK navigation to provide improved vertical and horizontal accuracies for the swath bathymetric data. RTK provides accuracies on the order of 10s of centimeters (http://www.navcen.uscg.gov/).

How was the data set created?

  1. From what previous works were the data drawn?
    Information unavailable from original metadata (source 1 of 1)
    Information unavailable from original metadata - assumed USGS, unknown, Information unavailable from original metadata.

    Type_of_Source_Media: Information unavailable from original metadata
    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 for the swath bathymetric system. 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 (UTC) for the beginning of the file, and DDD is the Julian day. Times in the file were recorded in UTC (Coordinate Universal Time).
  2. How were the data generated, processed, and modified?
    Date: 2007 (process 1 of 5)
    Raw HYPACK navigation files were transferred from the navigation acquisition computer to a Macintosh RAID server for accessibility and archival. The raw HYPACK navigation files are stored in separate directories indicating the acquisition Julian Day (JD221 through JD225), corresponding to August 9, 2007 - August 13, 2007. The filenames in each folder are in the format of linenumber_starttime.julianday. For example, filename 064_0057.224 represents HYPACK line number 064, start time 0057 and Julian Day 224. Times are recorded in UTC (Coordinate Universal Time). Person who carried out this activity:
    Jane F. Denny
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA

    (508) 548-8700 x2311 (voice)
    (508) 457-2310 (FAX)
    jdenny@usgs.gov
    Date: 19-Oct-2017 (process 2 of 5)
    Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Reordered the links in the identification section so a landing page link is first. Attempted to modify http to https where appropriate. The source information was incomplete and had to be modified to meet the standard. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 3 of 5)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 4 of 5)
    Crossref DOI link was added as the first link in the metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    HYPACK, Inc, 2009, HYPACK Hydrographic Survey Software User Manual.

    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?
    Real-Time Kinematic (RTK) data were collected using an Ashtech Z-Extreme receiver and were processed and recorded using navigation software from HYPACK, Inc (http://www.hypack.com/). These data were not incorporated into the geophysical data during acquisition. These data were stored in order to post-process the RTK navigation to provide improved vertical and horizontal accuracies for the swath bathymetric data during post-cruise processing. RTK provides accuracies on the order of 10s of centimeters (http://www.navcen.uscg.gov/).
  3. How accurate are the heights or depths?
    Data from the Z-Extreme were also logged to Ashtech's Geodetic Base Station Software (GBSS), and recorded locally to hard disk. GPS signal correction data from a Z-Extreme base station located at the USGS warehouse facility were transmitted via radio modem out to the ship. These data were used by the HYPACK software to provide height offsets from the WGS 84 ellipsoid. These offsets were then translated to water level heights based on the 2003 geoid model (see: http://www.ngs.noaa.gov/GEOID/GEOID03/ for more information), which approximates mean seal level (MSL).
  4. Where are the gaps in the data? What is missing?
    These files represent all the real-time kinematic (RTK) navigation recorded by the HYPACK software during USGS cruise 07011 off the southern shore of Martha's Vineyard, 2007.
  5. How consistent are the relationships among the observations, including topology?
    These are the original raw data files recorded by the HYPACK navigation software. 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:
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)
    Jane F. Denny
    U.S. Geological Survey
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA

    (508) 548-8700 x2311 (voice)
    (508) 457-2310 (FAX)
    jdenny@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?
    • Availability in digital form:
      Data format: This WinZip (version 9.0) file contains the ANSI text HYPACK navigation files as well as the associated metadata files. in format HYPACK (version Information unavailable from original metadata) Size: 27
      Network links: https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Nav/hypack.zip
    • Cost to order the data: None.

  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, such as WinZip or pkUnzip.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Jane F. Denny
U.S. Geological Survey
Marine Geologist
Woods Hole Coastal and Marine Science Center
Woods Hole, MA

(508) 548-8700 x2311 (voice)
(508) 457-2310 (FAX)
jdenny@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2008-1288/07011_hypack.faq.html>
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