j483hb.m77t and j483hb.h77t: MGD77T data and header files for single-beam bathymetry data for field activity J-4-83-HB in Humboldt Bay, California from 08/16/1983 to 08/19/1983

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Frequently anticipated questions:


What does this data set describe?

Title:
j483hb.m77t and j483hb.h77t: MGD77T data and header files for single-beam bathymetry data for field activity J-4-83-HB in Humboldt Bay, California from 08/16/1983 to 08/19/1983
Abstract:
Single-beam bathymetry data along with miniranger navigation data was collected as part of the U.S. Geological Survey cruise J-4-83-HB. The cruise was conducted in Humboldt Bay, California from August 16 to August 19, 1983. The chief scientist was John Dingler from the USGS Coastal and Marine Geology office in Menlo Park, CA. The purpose of the cruise was to conduct a survey of the underwater exterior and related features of both Humboldt Bay jetties and the Crescent City Outer Breakwater. The geophysical source was a Raytheon 7 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/j/j483hb/html/j-4-83-hb.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 miniranger. The miniranger system is a range-range system that utilizes radar frequencies in the X band. It is limited to line of sight operation between two or more fixed transponders, but an individual reading can be accurate to 3 meters. This miniranger data was collected in the NAD27 (Clarke 1866) horizontal datum. 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 with a Raytheon 7 kHz system as analog records and hand-digitized. 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, 2013, j483hb.m77t and j483hb.h77t: MGD77T data and header files for single-beam bathymetry data for field activity J-4-83-HB in Humboldt Bay, California from 08/16/1983 to 08/19/1983: 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., 2013, 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: -124.24744
    East_Bounding_Coordinate: -124.21581
    North_Bounding_Coordinate: 40.77624
    South_Bounding_Coordinate: 40.73740
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 16-Aug-1983
    Ending_Date: 19-Aug-1983
    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: Humboldt Bay, California from 08/16/1983 to 08/19/1983
      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 North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.98.
  7. How does the data set describe geographic features?
    j483hb.m77t
    MGD77T single-beam bathymetry data file for J483HB (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:19830816
    Maximum:19830819
    Units:YYYYMMDD, (four digit year, two digit month, two digit day)
    TIME
    Time (Source: NGDC)
    Range of values
    Minimum:621.5
    Maximum:1920
    Units:hours and decimal minutes
    LAT
    Latitude (Source: North American Datum of 1927 Geographic Coordinate System)
    Range of values
    Minimum:40.7374
    Maximum:40.77624
    Units:decimal degrees
    LON
    Longitude (Source: North American Datum of 1927 Geographic Coordinate System)
    Range of values
    Minimum:-124.24744
    Maximum:-124.21581
    Units:decimal degrees
    POS_TYPE
    Indicates how lat/lon was obtained (Source: NGDC)
    ValueDefinition
    1Observed fix
    3Interpolated fix
    nilunspecified
    BAT_TTIME
    Bathymetry, 2-way travel time (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.00653
    Maximum:0.10533
    Units:seconds
    j483hb.h77t
    MGD77T single-beam bathymetry header file for J-4-83-HB (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
    FORMAT_77
    Format Acronym (Source: NGDC) Text string description
    PARAMS_CO
    Parameters surveyed codes. (Source: NGDC) Status of geophysical parameters for this survey. See Hittelman and others (2010) from the Cross_Reference section above for details.
    INST_SRC
    Source Institution (Source: NGDC) Text string description
    COUNTRY
    Country (Source: NGDC) Text string description
    PLATFORM
    Platform name (Source: NGDC) Text string description
    PLAT_TYPCO
    Platform type code (Source: NGDC)
    ValueDefinition
    nilUnspecified
    1Surface Ship
    2Submersible Ship
    3Aircraft
    4Buoy
    5Mobile land
    6Fixed land
    7Deep tow
    PLAT_TYP
    Platform type (Source: NGDC) Text string description
    CHIEF
    Chief Scientist(s) (Source: NGDC) Text string description
    PROJECT
    Project, cruise, leg (Source: NGDC) Text string description
    FUNDING
    funding (Source: NGDC) Text string description
    DATE_DEP
    survey departure date (Source: NGDC)
    Range of values
    Minimum:19770427
    Maximum:20000629
    Units:YYYYMMDD (four digit year, two digit month, two digit day)
    PORT_DEP
    port of departure (Source: NGDC) Text string description
    DATE_ARR
    survey arrival date (Source: NGDC)
    Range of values
    Minimum:19770427
    Maximum:20000629
    Units:YYYYMMDD (four digit year, two digit month, two digit day)
    PORT_ARR
    port of arrival (Source: NGDC) Text string description
    NAV_INSTR
    navigation instrumentation (Source: NGDC) Text string description
    POS_INFO
    position determination method/ geodetic datum (Source: NGDC) Text string description
    BATH_INSTR
    bathymetry instrumentation (Source: NGDC) Text string description
    BATH_ADD
    additional forms of bathymetry (Source: NGDC) Text string description
    LAT_TOP
    Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:16.38240
    Maximum:89.98766
    Units:decimal degrees
    LAT_BOTTOM
    Latitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:16.38240
    Maximum:89.98766
    Units:decimal degrees
    LON_LEFT
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:10.30551
    Maximum:-117.13802
    Units:decimal degrees
    LON_RIGHT
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:10.30551
    Maximum:-117.13802
    Units:decimal degrees
    BATH_DRATE
    general digitizing rate of bathymetry (Source: NGDC) Text string description
    SOUND_VEL
    assumed sound velocity (Source: NGDC) Text string description
    VDATUM_CO
    bathymetric vertical datum (Source: NGDC) In our datasets, no correction was applied. All values equal 0.
    Entity_and_Attribute_Overview:
    Bathymetry and navigation data for U.S. Geological Survey bathymetry survey J-4-83-HB 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. The MGD77T format contains more attributes than defined here. Attributes that were null for this data were not included. Details about other attributes can be found in Hittelman and others (2010), 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?
    John Dingler (Chief Scientist, USGS Western Region);
  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: 14-Aug-2002 (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 Unknown 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/j/j483hb/bath/j-4-83-hb.330_651
    /infobank/programs/edit/automerge/automerge
    
    Input was...
    Converted to time format with year at start.
    
    04/23/85 BECKIE USR$DISK:[DRS.DATA.J483HB.B]J483HB.330;
    DRA1:[DRS.BAT]BATRED.EXE;1
    Bathymetry was hand-digetized in meters not travel time.
    
    04/23/85 BECKIE USR$DISK:[DRS.DATA.J483HB.B]J483HB.300;
    USR$DISK:[DRS.DATA.J483HB.B]J483.EXE;
    Bathymetry was hand-digetized in meters rather than travel time.
    
    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:
    • j-4-83-hb.651.txt
    Data sources produced in this process:
    • j483hbnav.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:
    • j-4-83-hb.335_651.txt
    Data sources produced in this process:
    • j483hbbathy.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:
    • j483hbbathy.txt, j483hbnav.txt
    Data sources produced in this process:
    • j483hball.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:
    • j483hball.txt
    Data sources produced in this process:
    • j483hb.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:
    • j483hb.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?
    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 (j-4-83-hb.651)
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    198308161255000    198308161304400
    198308161310350    198308161343050
    198308161349000    198308161452200
    198308161502320    198308161528200
    198308161544320    198308161548110
    198308161601170    198308161640110
    198308161649000    198308161713340
    198308161818450    198308161853250
    198308171304000    198308171353000
    198308171634000    198308171643000
    198308180621300    198308180631000
    198308180637350    198308180743260
    198308180756410    198308180935300
    198308180944190    198308181003250
    198308181033450    198308181052040
    198308181122400    198308181122550
    198308190834000    198308190955110
    198308191352150    198308191449400
    198308191540250    198308191610200
    198308191621150    198308191623450
    198308191629450    198308191643150
    198308191648550    198308191726000
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    Bathymetry Data (j-4-83-hb.330_651)
    YYYYMMDDHHMMSST    YYYYMMDDHHMMSST
    198308161255000    198308161302000
    198308161308000    198308161342000
    198308161349000    198308161402528
    198308161408000    198308161450198
    198308161500198    198308161529198
    198308161600300    198308161623000
    198308161631366    198308161639270
    198308161645000    198308161712000
    198308161821000    198308161852000
    198308161920000    198308161920000
    198308171304000    198308171346000
    198308171634000    198308171643000
    198308180621300    198308180631498
    198308180638000    198308180713000
    198308180719000    198308180743000
    198308180757000    198308180840450
    198308180851000    198308180935000
    198308180945300    198308181003000
    198308181041300    198308181050000
    198308190834000    198308190923000
    198308191357000    198308191449000
    198308191629450    198308191643000
    198308191651000    198308191708000
    198308191714000    198308191726000
    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_j483hb.faq.html>
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