f890nc.m77t and f890nc.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-8-90-NC in Gulf of Farallones, Northern California from 08/05/1990 to 08/17/1990

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Frequently anticipated questions:

What does this data set describe?

Title:
f890nc.m77t and f890nc.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-8-90-NC in Gulf of Farallones, Northern California from 08/05/1990 to 08/17/1990
Abstract:
Single-beam bathymetry data along with Loran-C RHO-RHO and GPS navigation data was collected as part of the U.S. Geological Survey cruise F-8-90-NC. The cruise was conducted in the Gulf of Farallones, Northern California from August 5 to August 17, 1990. The chief scientists were Herman Karl and Dave Drake 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. The purpose of this cruise was a slope stability survey of the Farallones Escarpment. The geophysical sources were 12 kilohertz (kHz), 10 kHz, and 3.5 kHz systems. 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/f890nc/html/f-8-90-nc.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 digitally collected using Loran-C RHO-RHO and a Global Positioning System (GPS). The GPS is a space-based satellite navigation system maintained by the United States government and is accessible using a GPS receiver. Data accuracy is based on individual receiver models, and most GPS data are collected in the WGS84 horizontal datum. Loran-C was a federally provided radionavigation service managed by the U.S. Coast Guard. Low frequency radio signals transmitted by fixed land based radio beacons served the 48 continental states, their coastal areas, and parts of Alaska. Loran-C could be utilized in different modes of operation; one of these was circular mode, also known as, range-range or RHO-RHO. It only needed a fix from two stations in order to establish a position and an accuracy of 20 to 40 m was achievable. 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 12 kHz, 10 kHz, 3.5 kHz systems. 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, f890nc.m77t and f890nc.h77t: MGD77T data and header files for single-beam bathymetry data for field activity F-8-90-NC in Gulf of Farallones, Northern California from 08/05/1990 to 08/17/1990: 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: -123.53189
    East_Bounding_Coordinate: -122.20077
    North_Bounding_Coordinate: 38.07073
    South_Bounding_Coordinate: 37.16215
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 05-Aug-1990
    Ending_Date: 17-Aug-1990
    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:
      Gulf of Farallones, Northern California from 08/05/1990 to 08/17/1990
      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?
    f890nc.m77t
    MGD77T single-beam bathymetry data file for F890NC (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:19900805
    Maximum:19900817
    Units:YYYYMMDD
    TIME
    Time (Source: NGDC)
    Range of values
    Minimum:0
    Maximum:2359.0167
    Units:hours and decimal minutes
    LAT
    Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:37.16215
    Maximum:38.07073
    Units:decimal degrees
    LON
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:-123.53189
    Maximum:-122.20077
    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:0.13333
    Maximum:117.39067
    Units:seconds
    Entity_and_Attribute_Overview:
    Bathymetry and navigation data for U.S. Geological Survey bathymetry survey F-8-90-NC 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?
    Herman Karl (Chief Scientist, USGS Western Region); Dave Drake (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: 31-Oct-2000 (process 1 of 9)
    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 
    Converted to time format with year at start.

11/06/90 MHAMER DRS$DATA:[F890NC.N]F890NC.052;1
DUA0:[DRS.PLT.NAVED.EXE]NAVED.EXE;
Integrated navigation (SINS) data
CLEANED UP NAVIGATION AS OF 11/6/90.  THIS IS THE FINAL VERSION WHICH
HAS BEEN CLEANED FOR THE 3.5 KHZ LINES AND CAMERA STATIONS.
    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: 31-Oct-1998 (process 2 of 9)
    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 
    10/31/1998  /lion/f/f890nc/bath/f-8-90-nc.300_052
/bear/programs/edit/automerge/automerge

Input was...
Converted to time format with year at start.

11/30/90 CAROLYN DRS$DATA:[F890NC.B]F890NC.300;1
DUA0:[DATA.][F790NC.B]REF.EXE;
Raw depth (bathymetry) data
from file DRS$DATA:[F890NC.B]RAWDEP_OUT.;1

Input was...
Converted to time format with year at start.

11/06/90 MHAMER DRS$DATA:[F890NC.N]F890NC.052;1
DUA0:[DRS.PLT.NAVED.EXE]NAVED.EXE;
Integrated navigation (SINS) data
CLEANED UP NAVIGATION AS OF 11/6/90.  THIS IS THE FINAL VERSION WHICH
HAS BEEN CLEANED FOR THE 3.5 KHZ LINES AND CAMERA STATIONS.

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 9)
    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-8-90-nc.052.txt
    Data sources produced in this process:
    • f890ncnav.txt
    Date: 2012 (process 4 of 9)
    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-8-90-nc.300_052.txt
    Data sources produced in this process:
    • f890ncbathy.txt
    Date: 2012 (process 5 of 9)
    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:
    • f890ncbathy.txt, f890ncnav.txt
    Data sources produced in this process:
    • f890ncall.txt
    Date: 2012 (process 6 of 9)
    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:
    • f890ncall.txt
    Data sources produced in this process:
    • f890nc.m77t
    Date: 2012 (process 7 of 9)
    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:
    • f890nc.h77t
    Date: 29-Dec-2016 (process 8 of 9)
    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: 13-Oct-2020 (process 9 of 9)
    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?
    Karl, H.A., Drake, D.E., Schwab, W.C., Edwards, B.D., Lee, H.J., and Chin, J.L., 1990, Progress report on status of analysis and interpretation of data collected on cruise F7-90-NC and F8-90-NC Farallon Escarpment, 19 July to 3 August and 5 to 17 August, 1990: U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: 25 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-8-90-nc.052 [SINS])
YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
199008051638460    199008051642010
199008051713510    199008051715060
199008051825340    199008051903000
199008051909300    199008081040010
199008081046000    199008082148010
199008082156000    199008082325010
199008082331000    199008090350040
199008090359030    199008091623000
199008091628010    199008100346000
199008100356000    199008111601010
199008111608000    199008111852050
199008111858100    199008111901010
199008111915010    199008112002020
199008112007030    199008130316000
199008130322030    199008131450010
199008131456200    199008151044000
199008151051000    199008170407000
YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
Bathymetry Data (f-8-90-nc.300_052)
YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
199008052324000    199008061830000
199008061842000    199008070206000
199008071354000    199008071442000
199008071454000    199008071542000
199008071554000    199008071800000
199008071812000    199008072048000
199008091120000    199008091226000
199008092024000    199008100036000
199008100048000    199008100318000
199008100954000    199008101154000
199008101348000    199008101448000
199008101636000    199008101724000
199008101912000    199008102024000
199008102224000    199008102330000
199008110230000    199008110342000
199008110406000    199008110754000
199008111006000    199008111106000
199008111354000    199008111518000
199008112100000    199008120106000
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: 13-Oct-2020
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_f890nc.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:48 2021