l1082bs.m77t - MGD77 data file for Geophysical data from field activity L-10-82-BS in Bering Sea, Alaska from 08/06/1982 to 08/24/1982

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title:
l1082bs.m77t - MGD77 data file for Geophysical data from field activity L-10-82-BS in Bering Sea, Alaska from 08/06/1982 to 08/24/1982
Abstract:
Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-10-82-BS in Bering Sea, Alaska from 08/06/1982 to 08/24/1982, http://walrus.wr.usgs.gov/infobank/l/l1082bs/html/l-10-82-bs.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/l1082bs/html/l-10-82-bs.bath.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.
Supplemental_Information:
The navigation data are digitally collected using a Satellite Integrated Navigation (SINS) system. The system is a space-based satellite navigation maintained by the United States government and is accessible using a satellite receiver. This system provides navigational accuracy of approximately 200 m.The Data Acquistion, Processing, and Storage (DAPS) group performs a number of processing steps to the navigation data once it is collected which can vary by cruise. These steps are outlined within the header information in each individual digital navigation (.05x) space-delimited ASCII data file. The header information rows are indicated by lines beginning with the character "!". There is no information on how the single-beam bathymetry, gravity, and magnetic data were collected. For each data gathering cruise leg, the available data in the following categories are forwarded to NGDC: navigation, gravity, magnetics, bathymetry, and seismic shot points. The available data for each cruise leg are re-formatted and combined into the Marine Geophysical Data Exchange Format (MGD77) and into the internal NGDC SEIS-NAV format by USGS using several USGS developed FORTRAN programs.The FORTRAN programs sample the navigation to every integer minute of the cruise. When necessary, the latitudes and longitudes are linearly interpolated. If the time between the actual navigation fixes exceeds five minutes, no data are included in the MGD77 file.To build the MGD77 file, gravity, magnetics, and bathymetry are added to this sampled navigation. When necessary, gravity, magnetics, and bathymetry data are linearly interpolated if the time between the actual data samples does not exceed five minutes. If a time gap exceeds this, the data are not reported.The navigation data are merged with the seismic shot point data in a SEIS- NAV format file. For this file, navigation data are interpolated for each shot point. Both types of files are written to magnetic tape and sent to NGDC.
  1. How might this data set be cited?
    U.S. Geological Survey, and Coastal and Marine Geology Program, 2013, l1082bs.m77t - MGD77 data file for Geophysical data from field activity L-10-82-BS in Bering Sea, Alaska from 08/06/1982 to 08/24/1982: 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: 178.13446
    East_Bounding_Coordinate: -165.39268
    North_Bounding_Coordinate: 64.49960
    South_Bounding_Coordinate: 57.48540
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-Aug-1982
    Ending_Date: 24-Aug-1982
    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: Bering Sea, Alaska
      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?
    l1082bs.m77t
    MGD77T single-beam bathymetry, gravity, and magnetics data file for L1082BS (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:19820806
    Maximum:19820824
    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:57.48540
    Maximum:64.49960
    Units:decimal degrees
    LON
    Longitude (Source: World Geodetic System 1984 Geographic Coordinate System)
    Range of values
    Minimum:-179.9997
    Maximum:179.9999
    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:0.038
    Maximum:4.884
    Units:seconds
    CORR_DEPTH
    Bathymetry, corrected depth (Source: U.S. Geological Survey)
    Range of values
    Minimum:28.5
    Maximum:3636
    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:51277.8
    Maximum:57265
    Units:gammas
    MAG_RES
    Magnetics residual field field (Source: NGDC)
    Range of values
    Minimum:-514.9
    Maximum:5231.6
    Units:gammas
    GRA_OBS
    Observed gravity (Source: NGDC)
    Range of values
    Minimum:981682.4
    Maximum:982297.6
    Units:milligals
    EOTVOS
    EOTVOS correction - E = 7.5 V cos(phi) * sin(alpha) + 0.0042 V*V (Source: NGDC)
    Range of values
    Minimum:-37
    Maximum:41.6
    Units:milligals
    FREEAIR
    Free-air Anomaly = G(observed) minus G(theoretical) (Source: NGDC)
    Range of values
    Minimum:-65.2
    Maximum:82.1
    Units:milligals
    Entity_and_Attribute_Overview:
    Bathymetry, gravity, magnetic, and navigation data for U.S. Geological Survey survey L1082BS in MGD77T format.
    Entity_and_Attribute_Detail_Citation:
    Attributes are obtained from MGD77T data files created from the navigation gravity, magnetic, 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?
    Paul Carlson (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: 19-Jan-1996 (process 1 of 7)
    Navigation Data >Converted to time format with year at start. > >06/13/85 KAYE USR$DISK:[DRS.DATA.L1082BS.N]L082BS.054; >USR$DISK:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l082bs.sinse1._. > 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 7)
    Gravity Data >10/31/1998 /tiger/l/l1082bs/grav/l-10-82-bs.151_054 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >10/09/85 BARB DRS$DATA:[LA82BS.G]LA82BS.151; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 > >Input was... >Converted to time format with year at start. > >06/13/85 KAYE USR$DISK:[DRS.DATA.L1082BS.N]L082BS.054; >USR$DISK:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l082bs.sinse1._. > >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: 20-Jun-2012 (process 3 of 7)
    Magnetics Data >06/20/2012 carolyn l-10-82-bs.220_054 > >Reprocessed using subroutines from Susan Macmillan's >IGRF SYNTHESIS PROGRAM http://www.ngdc.noaa.gov/IAGA/vmod/igrf11.f >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/l1082bs/mag/l-10-82-bs.200_054 >/bear/programs/edit/automerge/automerge > >Converted to time format with year at start. > >09/25/85 CAROLYN DRS$DATA:[LA82BS.M]LA82BS.200; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was L1082BS._.MAGSB1 on TAM403 >was L082BS220.DAT on VAM403 > >Converted to time format with year at start. > >06/13/85 KAYE USR$DISK:[DRS.DATA.L1082BS.N]L082BS.054; >USR$DISK:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l082bs.sinse1._. > >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: 31-Oct-1998 (process 4 of 7)
    Bathymetry Data >10/31/1998 /tiger/l/l1082bs/bath/l-10-82-bs.335_054 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >09/13/85 BECKIE DUA0:[DATA.LA82BS.B]LA82BS.335; >DRB0:[DRS.BAT]BATRED.EXE;1 >This file was hand-digetized in 2-way traveltime(secs). > >Input was... >Converted to time format with year at start. > >06/13/85 KAYE USR$DISK:[DRS.DATA.L1082BS.N]L082BS.054; >USR$DISK:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l082bs.sinse1._. > >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: 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-10-82-bs.054 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198208061946000 198208132006000 >198208132012000 198208170245000 >198208170311000 198208180104000 >198208180117000 198208180247000 >198208180321000 198208180757000 >198208180831000 198208241814560 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Gravity Data (l-10-82-bs.151_054) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198208062020180 198208062058180 >198208062128180 198208070055180 >198208070106180 198208070123180 >198208070136180 198208071411180 >198208071444180 198208081344180 >198208081350000 198208081407000 >198208081420000 198208090201540 >198208090213000 198208091204300 >198208091226300 198208100206480 >198208100225480 198208100419540 >198208100429420 198208101428360 >198208101444360 198208102050360 >198208102109360 198208102149360 >198208102157000 198208111028300 >198208111045300 198208111535420 >198208111544000 198208111946000 >198208112121480 198208112247480 >198208120010540 198208120151540 >198208120417420 198208120747360 >198208120804480 198208121455420 >198208121552000 198208121639000 >198208121732000 198208122111000 >198208130239000 198208130523000 >198208130559000 198208130734000 >198208130749000 198208130820000 >198208130832000 198208130932000 >198208130941000 198208131025000 >198208131610000 198208132219000 >198208132311000 198208140158000 >198208142036000 198208142301000 >198208142318000 198208150126000 >198208150335000 198208151712000 >198208151735000 198208160144000 >198208160959000 198208161151000 >198208161211000 198208161453000 >198208161520000 198208161753000 >198208161831240 198208170022120 >198208170144120 198208170241120 >198208170502120 198208171109360 >198208171134480 198208171237480 >198208172020480 198208172238540 >198208172244060 198208180625060 >198208180648060 198208181221420 >198208182155120 198208182300120 >198208182327120 198208190323120 >198208190738240 198208191003240 >198208191035240 198208191608240 >198208191617240 198208191620240 >198208191642240 198208192353240 >198208200051360 198208200633360 >198208200700000 198208200727360 >198208200751360 198208200920360 >198208200943360 198208201511360 >198208201542360 198208201936120 >198208210001480 198208210136300 >198208210726120 198208210923120 >198208211509480 198208211610480 >198208211624480 198208211709480 >198208211723480 198208211811120 >198208211827120 198208211906120 >198208211925120 198208211952120 >198208212004120 198208212040120 >198208212056120 198208212117120 >198208212129120 198208212205120 >198208212221120 198208212241120 >198208212253120 198208212320120 >198208212338120 198208220017120 >198208220033120 198208220109120 >198208220127120 198208220216120 >198208220231120 198208220258120 >198208220316120 198208220403120 >198208220417120 198208220447120 >198208220509120 198208220530300 >198208220551480 198208220831120 >198208220849120 198208221203300 >198208221325300 198208221820300 >198208221921300 198208222006120 >198208222040480 198208231026120 >198208231039120 198208231208120 >198208231225120 198208241044120 >198208241202120 198208241749120 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Magnetics Data (l-10-82-bs.220_054) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198208081813500 198208090207510 >198208090217590 198208100425070 >198208100434430 198208102155270 >198208102202030 198208111541070 >198208111548590 198208111952270 >198208112309500 198208120153200 >198208120352040 198208121505560 >198208161006200 198208161758580 >198208161836220 198208170026500 >198208170443250 198208171120050 >198208172038190 198208181227270 >198208182341300 198208190328250 >198208190743250 198208191614130 >198208191622240 198208201938130 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (l-10-82-bs.335_054) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >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_89-167/825.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:17:55 2021