k181hw.m77t - MGD77 data file for Geophysical data from field activity K-1-81-HW in Hawaii from 01/26/1981 to 02/05/1981

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Frequently anticipated questions:

What does this data set describe?

Title:
k181hw.m77t - MGD77 data file for Geophysical data from field activity K-1-81-HW in Hawaii from 01/26/1981 to 02/05/1981
Abstract:
Single-beam bathymetry data along with DGPS navigation data was collected as part of field activity K-1-81-HW in Hawaii from 01/26/1981 to 02/05/1981, http://walrus.wr.usgs.gov/infobank/k/k181hw/html/k-1-81-hw.meta.html The geophysical source was a Knudsen 12 kHz 320B/R echosounder. These data are reformatted from space-delimited ASCII text files located in the Coastal and Marine Geology Program (CMGP) InfoBank field activity catalog at http://walrus.wr.usgs.gov/infobank/k/k181hw/html/k-1-81-hw.bath.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.
Supplemental_Information:
The navigation data are digitally collected using a Satellite Integrated Navigation (SINS) system. The system is a space-based satellite navigation maintained by the United States government and is accessible using a satellite receiver. This system provides navigational accuracy of approximately 200 m.The Data Acquistion, Processing, and Storage (DAPS) group performs a number of processing steps to the navigation data once it is collected which can vary by cruise. These steps are outlined within the header information in each individual digital navigation (.05x) space-delimited ASCII data file. The header information rows are indicated by lines beginning with the character "!". There is no information on how the single-beam bathymetry, gravity, and magnetic data were collected. For each data gathering cruise leg, the available data in the following categories are forwarded to NGDC: navigation, gravity, magnetics, bathymetry, and seismic shot points. The available data for each cruise leg are re-formatted and combined into the Marine Geophysical Data Exchange Format (MGD77) and into the internal NGDC SEIS-NAV format by USGS using several USGS developed FORTRAN programs.The FORTRAN programs sample the navigation to every integer minute of the cruise. When necessary, the latitudes and longitudes are linearly interpolated. If the time between the actual navigation fixes exceeds five minutes, no data are included in the MGD77 file.To build the MGD77 file, gravity, magnetics, and bathymetry are added to this sampled navigation. When necessary, gravity, magnetics, and bathymetry data are linearly interpolated if the time between the actual data samples does not exceed five minutes. If a time gap exceeds this, the data are not reported.The navigation data are merged with the seismic shot point data in a SEIS- NAV format file. For this file, navigation data are interpolated for each shot point. Both types of files are written to magnetic tape and sent to NGDC.
  1. How might this data set be cited?
    U.S. Geological Survey, and Coastal and Marine Geology Program, 2013, k181hw.m77t - MGD77 data file for Geophysical data from field activity K-1-81-HW in Hawaii from 01/26/1981 to 02/05/1981: U.S. Geological Survey, Menlo Park, CA.

    Online Links:

    This is part of the following larger work.

    Steele, Wm. Clinton, Degnan, Carolyn H., Deeter, Gary B., and Riordan, Jean A., 1980, DESCRIPTION OF MARINE GEOPHYSICAL DATA COLLECTED BY THE U.S. GEOLOGICAL SURVEY AND HOW TO OBTAIN IT: U.S. Geological Survey Open File Report 167, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -158.35316
    East_Bounding_Coordinate: -155.20305
    North_Bounding_Coordinate: 21.42463
    South_Bounding_Coordinate: 18.83609
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 26-Jan-1981
    Ending_Date: 05-Feb-1981
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tab-delimited ASCII text files
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: Hawaii
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point
    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 1/298.25722210100002.
  7. How does the data set describe geographic features?
    k181hw.m77t
    MGD77T single-beam bathymetry data file for K181HW (Source: NOAA's National Geophysical Data Center, See Hittelman and others (2010) Cross_Reference section above for details about the MGD77T format and citation information.)
    SURVEY_ID
    Survey identifier supplied by the contributing organization (Source: NGDC) This identifier varies in format and is supplied by the contributing organization
    TIMEZONE
    Time-zone correction (Source: NGDC) In our datasets, no correction was applied. All values equal 0.
    DATE
    YYYYMMDD (Source: NGDC)
    Range of values
    Minimum:19810126
    Maximum:19810204
    Units:Year, month, day
    TIME
    Time (Source: NGDC)
    Range of values
    Minimum:0
    Maximum:2359
    Units:hours and decimal minutes
    LAT
    Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:18.83609
    Maximum:21.42458
    Units:decimal degrees
    LON
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:-158.35317
    Maximum:-155.20313
    Units:decimal degrees
    POS_TYPE
    Indicates how lat/lon was obtained (Source: NGDC)
    Range of values
    Minimum:1
    Maximum:3
    Units:1 = observed fix, 3 = interpolated fix, nil = unspecified
    BAT_TTIME
    Bathymetry, 2-way travel time (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.0159
    Maximum:4.0032
    Units:seconds
    CORR_DEPTH
    Bathymetry, corrected depth (Source: U.S. Geological Survey)
    Range of values
    Minimum:11.9
    Maximum:2989.3
    Units:decimal meters
    BAT_CPCO
    Bathymetric Correction code - details the procedure used for determining the sound velocity correction to depth (Source: NGDC)
    Range of values
    Minimum:63
    Maximum:63
    Units:01-55 Matthews' Zones with zone , 59 Matthews' Zones, no zone specified, 60 S. Kuwahara Formula, 61 Wilson Formula, 62 Del Grosso Formula, 63 Carter's Tables, 88 Other (see Add. Doc.), 97 Computed using 1500 meters/sec, 98 Unknown if Corrected, 99 Unspecified
    BAT_TYPCO
    Bathymetry type code - indicates how the bathymetric value was obtained (Source: NGDC)
    Range of values
    Minimum:1
    Maximum:3
    Units:1 - Observed, 3 - Interpolated (Header Seq. 12), 9 - Unspecified
    Entity_and_Attribute_Overview:
    Bathymetry and navigation data for U.S. Geological Survey bathymetry survey K181HW in MGD77T format.
    Entity_and_Attribute_Detail_Citation:
    Attributes are obtained from MGD77T data files created from the navigation and bathymetry best files. MGD77T is the standard, defined data format used for geophysical data in the National Geophysical Data Center. See Cross_Reference section above for citation details.

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
    • Coastal and Marine Geology Program
  2. Who also contributed to the data set?
    Bill Normark (Chief Scientist, USGS Western Region)
  3. To whom should users address questions about the data?
    Gregory K. Miller
    U.S. Geological Survey
    Physical Scientist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747, ext. 3020 (voice)
    gmiller@usgs.gov

Why was the data set created?

These data and information are intended for science researchers,students, policy makers, and general public. These data are not to be used for navigation purposes. The data are reformatted into MGD77T standard format for inclusion into NOAA's NGDC geophysical database. From there the data will be made available to GeoMapApp ( http://www.geomapapp.org/ ) and Virtual Ocean ( http://www.virtualocean.org/ ) Earth-browsing software. Access to the data is also provided via the USGS Coastal and Marine Geoscience Data System ( http://cmgds.marine.usgs.gov/ ).

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: 06-Dec-1995 (process 1 of 4)
    Navigation Data >Converted to time format with year at start. > >11/19/85 EDM USR$DISK:[CLINT.NAV1.K181HW]K181HW.052; >DRA1:[EDM]REFORMAT.EXE; > Person who carried out this activity:
    U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
    Attn: Carolyn H. Degnan
    Geophysicist
    USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
    Santa Cruz, CA
    USA

    (831) 460-7452 (voice)
    (831) 427-4748 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 07-Feb-2000 (process 2 of 4)
    Bathymetry Data >10/31/1998 /tiger/k/k181hw/bath/k-1-81-hw.305_052 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >12/23/85 BECKIE DISK$USERDISK:[BECKIE.TEMP]K181HW.305; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >This file appears to be hand-picked bathymetry >in meters. > >Input was... >Converted to time format with year at start. > >11/19/85 EDM USR$DISK:[CLINT.NAV1.K181HW]K181HW.052; >DRA1:[EDM]REFORMAT.EXE; > >time, lat, long, time(sec) to nearest nav fix, data values Person who carried out this activity:
    U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
    Attn: Carolyn H. Degnan
    Geophysicist
    USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
    Santa Cruz, CA
    USA

    (831) 460-7452 (voice)
    (831) 427-4748 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 01-Feb-2017 (process 3 of 4)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 19-Oct-2020 (process 4 of 4)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 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?
    Hittelman, Allen M., Groman, Robert C., Haworth, Richard T., Holcombe, Troy L., McHendrie, Graig, Smith, Stuart M., and Metzger, Dan R., 2010, The marine geophysical data exchange format - MGD77 / MGD77T: National Geophysical Data Center, National Oceanic and Atmospheric Administration, Boulder, CO.

    Online Links:

    Other_Citation_Details: 25 p.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The validity or accuracy of bathymetry and navigation data is highly qualitative and depends on equipment and operating condition variables. Data quality is unknown, MGD77T files were formatted from InfoBank files identified as best available version.
  2. How accurate are the geographic locations?
    Unspecified
  3. How accurate are the heights or depths?
    Unspecified
  4. Where are the gaps in the data? What is missing?
    Start and end date/times of data >Navigation Data (k-1-81-hw.052 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198101261430130 198101290827020 >198101290838590 198101291804230 >198101291823170 198101291830060 >198101291843090 198101291933360 >198101292011060 198101292244010 >198101292304450 198101292327570 >198101292346280 198101300207040 >198101300242340 198101300242340 >198101300344110 198101300417110 >198101300434300 198101300434300 >198101300522250 198101300600310 >198101300622310 198101300622310 >198101300722330 198101300734030 >198101300753000 198101300753000 >198101300839560 198101301352480 >198101301405240 198101301642010 >198101301701580 198101301747050 >198101301759000 198101301759000 >198101301836390 198101301909540 >198101301929540 198101301929540 >198101302020410 198101302101100 >198101302116060 198101302116060 >198101302147130 198101302219350 >198101302237300 198101302237300 >198101311929040 198101311929040 >198101311939490 198101311939490 >198102020248270 198102020306470 >198102020323240 198102020532380 >198102020543140 198102020747090 >198102020757140 198102021035140 >198102021046140 198102021250540 >198102021330490 198102021330490 >198102030156040 198102030609260 >198102031006360 198102032116360 >198102032128000 198102032128000 >198102032140540 198102032140540 >198102032154200 198102032345430 >198102040041470 198102040550460 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (k-1-81-hw.305_052) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198101261433440 198101261723140 >198101261740110 198101271044000 >198101271054020 198101272241280 >198101272252060 198101280239010 >198101280250100 198101281526000 >198101281539120 198101300236510 >198101300342400 198101300457490 >198101300524380 198101300615460 >198101300627230 198101300634020 >198101300644150 198101300644150 >198101300657080 198101300732350 >198101300838300 198101301751120 >198101301835260 198101301910400 >198101302020250 198101302101480 >198101302148250 198101302211500 >198101302253530 198101302307050 >198102012133280 198102012313170 >198102012324280 198102020545460 >198102020557120 198102020602110 >198102020614100 198102020832420 >198102020843540 198102020843540 >198102020854200 198102021237580 >198102021250300 198102021354500 >198102021408520 198102021419050 >198102021430430 198102021522090 >198102021556380 198102022018160 >198102022029110 198102030143320 >198102030242420 198102030557220 >198102030610100 198102030913010 >198102030949340 198102030949340 >198102030959550 198102031007180 >198102031020500 198102031020500 >198102031035560 198102031056080 >198102031108060 198102031322460 >198102031334100 198102031334100 >198102031346070 198102031346070 >198102031356490 198102031356490 >198102031407440 198102031422440 >198102031432460 198102031441490 >198102031453500 198102031531400 >198102031546040 198102031611200 >198102031621520 198102031641050 >198102031655550 198102031740150 >198102031751590 198102031751590 >198102031802400 198102031840280 >198102031858370 198102040209570 >198102040222280 198102040431160 >198102040446250 198102040512580 >198102040527170 198102040550080 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST
  5. How consistent are the relationships among the observations, including topology?
    This data set is from one field activity with unknown instrument calibrations. Processed bathymetric depths were spot checked based on latitude and longitude against the Global Multi-Resolution Topography (GMRT) grid within GeoMapApp to ensure reasonable values.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. These data are held in the public domain.
Use_Constraints:
This information is not intended for navigational purposes. Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data. Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    345 Middlefield Road MS 999
    Menlo Park, CA
    USA

    (650) 329-5078 (voice)
    (650) 329-5190 (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?

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2020
Metadata author:
Gregory K. Miller
U.S. Geological Survey
Physical Scientist
U.S. Geological Survey, 600 Fourth Street South
St. Petersburg, FL
USA

(727) 803-8747, ext. 3020 (voice)
gmiller@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/SeriesReports/OFR/OFR_89-167/815.faq.html>
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