l978hw.m77t - MGD77 data file for Geophysical data from field activity L-9-78-HW in Hawaii from 10/12/1978 to 10/19/1978

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Frequently anticipated questions:

What does this data set describe?

Title:
l978hw.m77t - MGD77 data file for Geophysical data from field activity L-9-78-HW in Hawaii from 10/12/1978 to 10/19/1978
Abstract:
Single-beam bathymetry, magnetics, and gravity data along with transit satellite navigation data was collected as part of field activity L-9-78-HW in Hawaii from 10/12/1978 to 10/19/1978, http://walrus.wr.usgs.gov/infobank/l/l978hw/html/l-9-78-hw.meta.html
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/l/l978hw/html/l-9-78-hw.bath.html http://walrus.wr.usgs.gov/infobank/l/l978hw/html/l-9-78-hw.grav.html http://walrus.wr.usgs.gov/infobank/l/l978hw/html/l-9-78-hw.mag.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, l978hw.m77t - MGD77 data file for Geophysical data from field activity L-9-78-HW in Hawaii from 10/12/1978 to 10/19/1978: 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: -157.88020
    East_Bounding_Coordinate: -154.75000
    North_Bounding_Coordinate: 21.30730
    South_Bounding_Coordinate: 18.64070
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Oct-1978
    Ending_Date: 19-Oct-1978
    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?
    l978hw.m77t
    MGD77T single-beam bathymetry, gravity, and magnetics data file for l978hw (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:19781012
    Maximum:19781019
    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:18.6407
    Maximum:21.3073
    Units:decimal degrees
    LON
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:-157.8802
    Maximum:-154.75
    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:0.04
    Maximum:6.345
    Units:seconds
    CORR_DEPTH
    Bathymetry, corrected depth (Source: U.S. Geological Survey)
    Range of values
    Minimum:30
    Maximum:4770.6
    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
    MAG_TOT
    Magnetics total field - 1st sensor (Source: NGDC)
    Range of values
    Minimum:33836
    Maximum:36653.9
    Units:gammas
    MAG_TOT2
    Magnetics total field - 2nd sensor (Source: NGDC)
    Range of values
    Minimum:33848.6
    Maximum:36650.6
    Units:gammas
    MAG_RES
    Magnetics residual field field (Source: NGDC)
    Range of values
    Minimum:-1674.9
    Maximum:1120.6
    Units:gammas
    MAG_RESSEN
    SENSOR FOR RESIDUAL FIELD (Source: NGDC)
    Range of values
    Minimum:1
    Maximum:1
    Units:1 - first sensor, 2 - second sensor, 9 - Unspecified
    Entity_and_Attribute_Overview:
    Bathymetry, magnetic, gravity, and navigation data for U.S. Geological Survey survey l978hw in MGD77T format.
    Entity_and_Attribute_Detail_Citation:
    Attributes are obtained from MGD77T data files created from the navigation, gravity, magnetics 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, Peter Lipman(Chief Scientist)
  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: 22-Jan-1996 (process 1 of 7)
    Navigation Data >Converted to time format with year at start. > >01/15/86 KAYE DUA0:[DATA.L978HW.N]L978HW.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >Edited DR's, sats and radar fixes. > Person who carried out this activity:
    U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
    Attn: Clint Steele
    InfoBank Group Leader
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA
    USA

    (650) 329-5055 (voice)
    (650) 329-5190 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 31-Oct-1998 (process 2 of 7)
    Gravity Data >10/31/1998 /tiger/l/l978hw/grav/l-9-78-hw.111_050 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >12/12/85 BARB DUA0:[DATA.L978HW.G]L978HW.111; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 > >Input was... >Converted to time format with year at start. > >01/15/86 KAYE DUA0:[DATA.L978HW.N]L978HW.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >Edited DR's, sats and radar fixes. > >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: Clint Steele
    InfoBank Group Leader
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA
    USA

    (650) 329-5055 (voice)
    (650) 329-5190 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 21-Jun-2012 (process 3 of 7)
    Magnetics Data >06/21/2012 carolyn l-9-78-hw.260_050 > >Reprocessed using subroutines from Susan Macmillan's >IGRF SYNTHESIS PROGRAM >with IGRF-11 coeffiecients integrated into the source code. >/infobank/programs/mag/magred11/magred11.for >Using geodetic coordinate system (Earth shape approximated by spheriod) >with altitude 0.0 km (for sea level). > >Input was... >10/31/1998 /tiger/l/l978hw/mag/l-9-78-hw.240_050 >/bear/programs/edit/automerge/automerge > >Converted to time format with year at start. > >01/22/86 CAROLYN DRS$DATA:[L978HW.M]L978HW.240; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >285/1401-287/1130 was L978HW.MAGSC1 from Clint >287/1130-289/1823 was L978HW._.MAGAC2 on TAM186 > L978HW220.DAT on VAM186 >289/1833-291/2245 was L978HW._.MAGSC3 on TAM187 > L978HW220.DAT on VAM187 > >Converted to time format with year at start. > >01/15/86 KAYE DUA0:[DATA.L978HW.N]L978HW.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >Edited DR's, sats and radar fixes. > >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: Clint Steele
    InfoBank Group Leader
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA
    USA

    (650) 329-5055 (voice)
    (650) 329-5190 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 31-Oct-1998 (process 4 of 7)
    Bathymetry Data >10/31/1998 /tiger/l/l978hw/bath/l-9-78-hw.335_050 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >12/06/85 BECKIE DUA0:[DATA.L978HW.B]L978HW.335; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >This file was hand-digetized in 2-way travel time (secs). >Velocity of sound assumed: 1500M/sec. > >Input was... >Converted to time format with year at start. > >01/15/86 KAYE DUA0:[DATA.L978HW.N]L978HW.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >Edited DR's, sats and radar fixes. > >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: Clint Steele
    InfoBank Group Leader
    USGS, MailStop 999, 345 Middlefield Road
    Menlo Park, CA
    USA

    (650) 329-5055 (voice)
    (650) 329-5190 (FAX)
    infobank@octopus.wr.usgs.gov
    Date: 20-Jun-2012 (process 5 of 7)
    MGD77 file creation - 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. 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 6 of 7)
    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 7 of 7)
    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 (l-9-78-hw.050 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197810120100000 197810151715340 >197810151735430 197810160335200 >197810160401130 197810160554520 >197810160614570 197810161230250 >197810161306000 197810161306000 >197810161330000 197810180335200 >197810180355230 197810180713310 >197810180738360 197810181355030 >197810181430040 197810181430040 >197810181514000 197810181514000 >197810181642020 197810190754530 >197810190820000 197810190820000 >197810190900000 197810190900000 >197810190930000 197810191000000 >197810191030000 197810191030000 >197810191100000 197810191200000 >197810191225000 197810191300000 >197810191330000 197810191509000 >197810191530000 197810191600000 >197810191630000 197810191630000 >197810191700000 197810191700000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Gravity Data (l-9-78-hw.111_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197810120100100 197810130705300 >197810130714000 197810151830400 >197810151838500 197810161051400 >197810161101200 197810191700000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Magnetics Data (l-9-78-hw.260_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197810121401580 197810122027040 >197810122058050 197810131853430 >197810140534370 197810161823290 >197810161833010 197810172229580 >197810180017210 197810182245320 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (l-9-78-hw.335_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197810120116420 197810121339000 >197810121344420 197810130520540 >197810130526480 197810131334540 >197810131340180 197810131801000 >197810131806120 197810140225060 >197810140311120 197810140514360 >197810140520180 197810140817360 >197810140823060 197810140827180 >197810140833060 197810141635540 >197810141641120 197810141654360 >197810141701120 197810141912120 >197810141921300 197810150037000 >197810150047300 197810151610480 >197810151616240 197810160502240 >197810160507300 197810161456060 >197810161502360 197810161642420 >197810161647480 197810161932360 >197810161937540 197810170106360 >197810170113240 197810170800000 >197810170805120 197810171006420 >197810171011480 197810171043180 >197810171048420 197810171136360 >197810171147060 197810171228360 >197810171234180 197810171443180 >197810171449420 197810171532300 >197810171538180 197810171538180 >197810171545000 197810171602240 >197810171608000 197810171941240 >197810171948420 197810180215000 >197810180227180 197810180309420 >197810180316240 197810180440060 >197810180446000 197810180554480 >197810180600060 197810180629480 >197810180635480 197810180640360 >197810180646300 197810181019240 >197810181025120 197810181108300 >197810181113480 197810181538120 >197810181544420 197810181753300 >197810181759120 197810181942060 >197810181947240 197810182214480 >197810182220000 197810182332000 >197810190400000 197810190445360 >197810190452360 197810191316300 >197810191327240 197810191541180 >197810191547420 197810191659180 >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_89-167/1318.faq.html>
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