f786hw.m77t and f786hw.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-7-86-HW in in Hawaii from 11/28/1986 to 12/20/1986

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Frequently anticipated questions:


What does this data set describe?

Title:
f786hw.m77t and f786hw.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-7-86-HW in in Hawaii from 11/28/1986 to 12/20/1986
Abstract:
Single-beam bathymetry data along with GPS navigation data was collected as part of the U.S. Geological Survey cruise F-7-86-HW. The cruise was conducted in Hawaii from November 28 to December 20, 1986. The chief scientists were Jim Hein from the USGS Coastal and Marine Geology office in Menlo Park, CA and Bill Schwab from the USGS Coastal and Marine Geology office in Woods Hole, Mass. This cruise had many purposes, the bathymetric data is a survey of a small area of the south Johnston Island ridge. The geophysical source was 3.5 kilohertz (kHz) system. 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/f/f786hw/html/f-7-86-hw.meta.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 collected using a Shipboard Integrated Navigation System (SINS). Transit satellite navigation and a number of subsystems are used in dead reckoning between satellite fixes. These included Doppler sonar, speed-of-sound velocimeter, water temperature sensor, gyrocompass, electromagnetic speed log, radionavigation and other subsystems. SINS was highly variable and at best there is a 50 m accuracy. The Data Acquisition, 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 (.0xx, .6xx) space-delimited ASCII data file. The header information rows are indicated by lines beginning with the character "!". The single-beam bathymetry data are collected both digitally and as analog records with a 3.5 kHz system. The bathymetry datasets were commonly processed using three programs: (A) Batred, which calculates depth from travel times; (B) nosamebathy, which eliminates identical adjacent bathymetry values; and (C) nozerobathy, which removes records with a depth value of "0.0". However, not all of the datasets included in this report were processed with one or more of these programs. If the data was not run through these programs it was reformatted using the most recent "best file" on InfoBank, often these were categorized by InfoBank as raw bathymetry files. Details about which processing steps were taken by the DAPS group can be found in the header information of the bathymetry and navigation ASCII files downloaded from InfoBank. Prior to reformatting the data into MGD77T format the "best" bathymetry and navigation files from InfoBank were edited to remove the header information and reformatted using Excel 2010 to separate the data into columns based on tabs. Next the bathymetry and navigation files were merged based on time and latitude and longitude. The combined navigation and bathymetry was saved as a .txt file. This combined bathymetry and navigation file was used as an input file into the GEODAS ReFormat to MDG77T program developed by NOAA's NGDC. The program outputs the reformatted data as a tab-delimited .m77t file. The program is available for use at: http://www.ngdc.noaa.gov/mgg/gdas/gx_announce.Html. For information regarding fields found within the MGD77T files, please refer to the publication, Hittelman and others (2010), found within the Cross-reference section of this metadata file. Each MGD77T data file also has an accompanying header file (.h77t). The fields within these header files are also defined in the aforementioned publication. Fields are populated based on InfoBank metadata records, digital data file headers, and accompanying publications (often cruise reports) for the survey. If a field is unknown or did not apply to the dataset it is intentionally left blank. .
  1. How might this data set be cited?
    U.S. Geological Survey, and Coastal and Marine Geology Program, 2012, f786hw.m77t and f786hw.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-7-86-HW in in Hawaii from 11/28/1986 to 12/20/1986: U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

    This is part of the following larger work.

    Schreppel, Heather A., Degnan, Carolyn H., Metzger, Dan R., and Dadisman, Shawn V., 2012, Archive of U.S. Geological Survey selected single-beam bathymetry datasets, 1969-2000: U.S. Geological Survey Data Series 757, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -169.59520
    East_Bounding_Coordinate: -157.96300
    North_Bounding_Coordinate: 21.25430
    South_Bounding_Coordinate: 16.38240
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 28-Nov-1986
    Ending_Date: 20-Dec-1986
    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 from 11/28/1986 to 12/20/1986
      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?
    f786hw.m77t
    MGD77T single-beam bathymetry data file for F786HW (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
    Survey date (Source: NGDC)
    Range of values
    Minimum:19861129
    Maximum:19861212
    Units:YYYYMMDD
    TIME
    Time (Source: NGDC)
    Range of values
    Minimum:0
    Maximum:2359.7833
    Units:hours and decimal minutes
    LAT
    Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:16.3824
    Maximum:21.2543
    Units:decimal degrees
    LON
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:-169.5952
    Maximum:-157.963
    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:2.01923
    Maximum:7.16646
    Units:seconds
    Entity_and_Attribute_Overview:
    Bathymetry and navigation data for U.S. Geological Survey bathymetry survey F-7-86-HW 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?
    Jim Hein (Chief Scientist, USGS Western Region); Bill Schwab (Chief Scientist, USGS Woods Hole)
  3. To whom should users address questions about the data?
    Heather A. Schreppel
    Cherokee Nation Technology Solutions, contracted to U.S. Geological Survey
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747, ext. 3013 (voice)
    hschreppel@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: 30-Aug-1996 (process 1 of 8)
    Below are the details about which processing steps were taken by the DAPS group that can be found in the header information of the ASCII files downloaded from InfoBank. Navigation Data
    08/30/96 CAROLYN MOG$DUB2:[REQUESTS.HEIN.KARIN]F-7-86-HW.055;1
    MOG$DUB0:[PROGRAMS.REFMT]VMS2UNIX.EXE;1
    Integrated navigation (SINS) data
    
    Input was...
    04/02/91 MHAMER DRS$DATA:[HEIN.KARIN.BATHY]F786HW.055;1
    DUA0:[DRS.REFMT]DXFMT_TO_DAPS.EXE;
    Integrated navigation (SINS) data
    REFORMATTED FROM DXFMT FORMAT
    
    
    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: 03-Nov-2008 (process 2 of 8)
    Below are the details about which processing steps were taken by the DAPS group that can be found in the header information of the ASCII files downloaded from InfoBank. Bathymetry Data
    11/03/2008 jpaz /infobank/f/f786hw/bath/f-7-86-hw.300_055
    /infobank/programs/edit/automerge/automerge
    
    Input was...
    08/30/96 CAROLYN MOG$DUB2:[REQUESTS.HEIN.KARIN]F-7-86-HW.300;1
    MOG$DUB0:[PROGRAMS.REFMT]VMS2UNIX.EXE;1
    Raw depth (bathymetry) data
    
    08/30/96 CAROLYN MOG$DUB2:[REQUESTS.HEIN.KARIN]F786HW.300;1
    MOG$DUB2:[REQUESTS.HEIN.KARIN]TEMP.EXE;
    Raw depth (bathymetry) data
    reformatted MOG$DUB2:[REQUESTS.HEIN.KARIN]F786HW_BATHY.DIGIT
    
    Input was...
    08/30/96 CAROLYN MOG$DUB2:[REQUESTS.HEIN.KARIN]F-7-86-HW.055;1
    MOG$DUB0:[PROGRAMS.REFMT]VMS2UNIX.EXE;1
    Integrated navigation (SINS) data
    
    04/02/91 MHAMER DRS$DATA:[HEIN.KARIN.BATHY]F786HW.055;1
    DUA0:[DRS.REFMT]DXFMT_TO_DAPS.EXE;
    Integrated navigation (SINS) data
    REFORMATTED FROM DXFMT FORMAT
    
    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: 2012 (process 3 of 8)
    A navigation file identified as the best available version in InfoBank for this cruise was copied and saved as an ASCII text file to be combined with the best available bathymetry file for processing to MGD77T format. For details regarding processing steps performed on these best available files from InfoBank, please see the header information within the original files at http://walrus.wr.usgs.gov/infobank/ and previous processing steps. Person who carried out this activity:
    Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
    Attn: Heather A. Schreppel
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    727-803-8747 ext. 3013 (voice)
    hschreppel@usgs.gov
    Data sources used in this process:
    • f-7-86-hw.055.txt
    Data sources produced in this process:
    • f786hwnav.txt
    Date: 2012 (process 4 of 8)
    A bathymetry file identified as the best available version in InfoBank for this cruise was copied and saved as an ASCII text file to be combined with the best available navigation file for processing to MGD77T format. For details regarding processing steps performed on these best available files from InfoBank, please see the header information within the original files at http://walrus.wr.usgs.gov/infobank/. Person who carried out this activity:
    Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
    Attn: Heather A. Schreppel
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    727-803-8747 ext. 3013 (voice)
    hschreppel@usgs.gov
    Data sources used in this process:
    • f-7-86-hw.300_055.txt
    Data sources produced in this process:
    • f786hwbathy.txt
    Date: 2012 (process 5 of 8)
    The best available bathymetry and navigation text files were concatenated into one tab-delimited file using Excel 2010 and several Visual Basic Applications (VBA) macros. InfoBank header information is removed and text is broken into columns and the rows are combined based on the presence of the same values in the time and latitude and longitude columns. Person who carried out this activity:
    Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
    Attn: Heather A. Schreppel
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    727-803-8747 ext. 3013 (voice)
    hschreppel@usgs.gov
    Data sources used in this process:
    • f786hwbathy.txt, f786hwnav.txt
    Data sources produced in this process:
    • f786hwall.txt
    Date: 2012 (process 6 of 8)
    The combined bathymetry and navigation file was used as an input file into the GEODAS ReFormat to MDG77T program developed by NOAA's NGDC. The program outputs the reformatted data as a tab-delimited .m77t file. The program is available for use at: http://www.ngdc.noaa.gov/mgg/gdas/gx_announce.Html Person who carried out this activity:
    Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
    Attn: Heather A. Schreppel
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    727-803-8747 ext. 3013 (voice)
    hschreppel@usgs.gov
    Data sources used in this process:
    • f786hwall.txt
    Data sources produced in this process:
    • f786hw.m77t
    Date: 2012 (process 7 of 8)
    To create the accompanying header files (.h77t), an excel spreadsheet was supplied from NGDC with already populated required field names. For information for header field requirements and definitions see: http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.pdf. When creating a header file for each cruise, fields were populated in the header spreadsheet based on InfoBank metadata records, digital data file headers, and accompanying publications (often cruise reports) for the survey. If a field was unknown or did not apply to the dataset it was intentionally left blank. Person who carried out this activity:
    Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
    Attn: Heather A. Schreppel
    IT Management Specialist/Database Support Assistant
    600 4th Street South
    St. Petersburg, FL
    USA

    727-803-8747 ext. 3013 (voice)
    hschreppel@usgs.gov
    Data sources used in this process: Data sources produced in this process:
    • f786hw.h77t
    Date: 29-Dec-2016 (process 8 of 8)
    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
  3. What similar or related data should the user be aware of?
    Hein, James R., Schwab, William C., Foot, Donald G., Masuda, Yoshio, Usui, Akira, Davis, Alice S., Fleishman, Charlaine L., Barna, David L., Pickthorn, Leda-Beth, Larson, David A., Ruzzi, Peter, Benninger, Laura M., and Gein, Lisa M., 1987, Farnella Cruise F7-86-HW, Cobalt-rich Ferromanganese Crust Data Report for Karin Ridge and Johnston Island, Central Pacific: U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: 37 p.
    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 according to DAPS group. Reasons for gaps in data varies by cruise, see InfoBank for more details.
    Navigation Data (f-7-86-hw.055 [SINS])
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    198611290426000    198612120316000
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    Bathymetry Data (f-7-86-hw.300_055)
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    198612011224020    198612011841550
    198612011852010    198612011903590
    198612011918080    198612020303420
    198612020315110    198612020423310
    198612050748070    198612050841380
    198612050854160    198612050941270
    198612050953420    198612051623010
    198612051642010    198612051842020
    198612052024390    198612060029290
    198612060044120    198612060215520
    198612060247090    198612060659310
    198612060720380    198612061217120
    198612061248020    198612061724050
    198612061736020    198612061753540
    198612061906270    198612062142010
    198612062200020    198612062248020
    198612070059360    198612070129490
    198612070141560    198612070359440
    198612070412060    198612070511570
    198612100642010    198612100738280
    198612100754260    198612100926210
    198612100945400    198612101100010
    198612101114400    198612101118070
    198612101128440    198612101141300
    198612101423590    198612101518070
    198612101529380    198612101612020
    198612101630060    198612101705590
    198612101716290    198612101716290
    198612101736050    198612102247580
    198612102312060    198612110317320
    198612110547200    198612110817450
    198612110905520    198612110951110
    198612111001580    198612111205470
    198612111218140    198612111242070
    198612111259210    198612111351310
    198612111418300    198612111434200
    198612111449420    198612111545050
    198612111557180    198612111635460
    198612111659510    198612112220160
    198612112233080    198612120053170
    198612120105590    198612120111580
    198612120123320    198612120159550
    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.

Who wrote the metadata?

Dates:
Last modified: 29-Dec-2016
Metadata author:
Heather A. Schreppel
Cherokee Nation Technology Solutions, contracted to the U.S. Geological Survey
IT Management Specialist/Database Support Assistant
U.S. Geological Survey, 600 Fourth Street South
St. Petersburg, FL
USA

(727) 803-8747, ext. 3013 (voice)
hschreppel@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/DS757_f786hw.faq.html>
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