U.S. Geological Survey
Coastal and Marine Geology Program
2013
l475bs.m77t - MGD77 data file for Geophysical data from field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975
tab-delimited ASCII text files
Menlo Park, CA
U.S. Geological Survey
http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l475bs/mgd77/
Wm. Clinton Steele
Carolyn H. Degnan
Gary B. Deeter
Jean A. Riordan
1980
DESCRIPTION OF MARINE GEOPHYSICAL DATA COLLECTED BY THE U.S. GEOLOGICAL SURVEY AND HOW TO OBTAIN IT
1.0
Digital Document
U.S. Geological Survey Open File Report
167
Menlo Park, CA
U.S. Geological Survey
http://pubs.usgs.gov/of/1989/0167/report.pdf
Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975, http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-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/l475bs/html/l-4-75-bs.bath.html, http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.grav.html, and http://walrus.wr.usgs.gov/infobank/l/l475bs/html/l-4-75-bs.mag.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.
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/ ).
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.
19750907
19750918
ground condition
None planned
-169.05780
-165.50410
57.21860
54.02090
USGS Metadata Identifier
USGS:c0e258a9-8c41-46a9-adce-2a7683c42be7
ISO 19115 Topic Category
geoscientificinformation
oceans
None
Marine Geology
Marine Geophysics
Marine Gravity Field
Marine Magnetic Field
Magnetic Anomalies
Bathymetry
Water Depth
Seafloor Topography
Data Categories for Marine Planning
distributions
bathymetry and elevation
Marine Realms Information Bank (MRIB) keywords
single-beam echo sounder
gravimetry
magnetic field observations
marine geophysics
USGS Thesaurus
single-beam echo sounder
bathymetry measurement
bathymetry
gravimeter measurement
magnetometer measurement
marine geophysics
Geographic Names Information System (GNIS)
AK
Alaska
Aleutian Arc
Bering Sea
Bering Sea, Aleutian Basin, Alaska
USA
None. These data are held in the public domain.
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.
Gregory K. Miller
U.S. Geological Survey
Physical Scientist
mailing and physical
600 4th Street South
St. Petersburg
FL
33701
USA
(727) 803-8747, ext. 3020
gmiller@usgs.gov
Alan Cooper (Chief Scientist)
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
Boulder, CO
National Geophysical Data Center, National Oceanic and Atmospheric Administration
25 p.
http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.pdf
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.
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.
Start and end date/times of data >Navigation Data (l-4-75-bs.050 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197509071906000 197509160135000 >197509160147000 197509160147000 >197509160159000 197509160159000 >197509160211000 197509160211000 >197509160223000 197509160223000 >197509160235000 197509160235000 >197509160247000 197509160247000 >197509160259000 197509160259000 >197509160311000 197509160311000 >197509160323000 197509160323000 >197509160335000 197509160335000 >197509160347000 197509160347000 >197509160359000 197509180100000 >197509180130000 197509180130000 >197509180200000 197509180200000 >197509180300000 197509180300000 >197509180320000 197509180320000 >197509180340000 197509180340000 >197509180400000 197509181126000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Gravity Data (l-4-75-bs.160_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197509071906000 197509072219000 >197509072240000 197509081259000 >197509081308000 197509081719000 >197509081941000 197509082049000 >197509082121000 197509090616000 >197509110125000 197509110510000 >197509110602000 197509110708000 >197509142342000 197509150219000 >197509150406000 197509151125000 >197509151150000 197509151859000 >197509152202000 197509160324000 >197509160501000 197509161431000 >197509161437000 197509161603000 >197509161609000 197509161619000 >197509161653000 197509162138000 >197509162201000 197509170147000 >197509170240000 197509172029000 >197509172036000 197509180100000 >197509180532000 197509181125000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Magnetics Data (l-4-75-bs.220_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197509072113480 197509072300420 >197509072320300 197509072326360 >197509072339120 197509072359179 >197509080044240 197509082003300 >197509082013539 197509082038000 >197509082045240 197509091223479 >197509150150059 197509151900420 >197509161938120 197509172358420 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (l-4-75-bs.335_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197509071906000 197509072259000 >197509080644000 197509081123000 >197509081139000 197509090642000 >197509090648000 197509090724000 >197509091308000 197509091400000 >197509101730000 197509102136000 >197509102143000 197509110028000 >197509150238000 197509150257000 >197509150303000 197509151117000 >197509151220000 197509151354000 >197509151400000 197509151404000 >197509151410000 197509151415000 >197509151421000 197509151649000 >197509151723000 197509160212000 >197509160528000 197509161304000 >197509161314000 197509161626000 >197509161645000 197509170150000 >197509170240000 197509171237000 >197509171248000 197509171313000 >197509171327000 197509171903000 >197509171916000 197509172235000 >197509172343000 197509181126000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Seismic Shots Data (l-4-75-bs.420_050) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197509072030000 197509072100000 >197509072110060 197509072251540 >197509072312000 197509072312000 >197509072347240 197509080027000 >197509080037540 197509080227060 >197509080243300 197509080318000 >197509080328360 197509080342180 >197509080358480 197509080642180 >197509080752240 197509080840420 >197509080852540 197509080923480 >197509080935420 197509081003120 >197509081016060 197509081126480 >197509081138000 197509081237120 >197509081252540 197509081252540 >197509081313540 197509081313540 >197509081325240 197509081417540 >197509081428120 197509081522060 >197509081535240 197509081828480 >197509081844240 197509081915060 >197509082143480 197509082202540 >197509082221000 197509082237120 >197509082303180 197509082326300 >197509082348360 197509082348360 >197509082358540 197509082358540 >197509090010060 197509090010060 >197509090021180 197509090021180 >197509090032180 197509090032180 >197509090044180 197509090044180 >197509090054360 197509090054360 >197509090107060 197509090107060 >197509090914240 197509090929420 >197509090942120 197509091005300 >197509142345000 197509142345000 >197509152024000 197509152024000 >197509160457000 197509160514060 >197509160524300 197509160556300 >197509160608480 197509160618000 >197509160634060 197509160634060 >197509160645120 197509160813480 >197509160827420 197509160827420 >197509160840240 197509160911060 >197509160931180 197509160948120 >197509161001120 197509161016240 >197509161041060 197509161104540 >197509161123240 197509161151480 >197509161202360 197509161202360 >197509161214360 197509161251540 >197509161330240 197509161359120 >197509161412300 197509161521120 >197509161538000 197509161612060 >197509161622480 197509161622480 >197509161647480 197509161822420 >197509162205480 197509162231060 >197509162247480 197509162247480 >197509162259060 197509162259060 >197509162318240 197509162334180 >197509162354180 197509170012300 >197509170026060 197509170026060 >197509170037000 197509170053300 >197509170103480 197509170109480 >197509170122300 197509170136300 >197509170150000 197509170150000 >197509170240120 197509170347540 >197509170358240 197509170803060 >197509170814360 197509170823360 >197509170834180 197509170850480 >197509170901420 197509170910060 >197509170929360 197509171027240 >197509171040540 197509171040540 >197509171052420 197509171052420 >197509171103360 197509171103360 >197509171116540 197509171116540 >197509171127540 197509171127540 >197509171139000 197509171149000 >197509171201360 197509171208300 >197509171221180 197509171221180 >197509171231540 197509171231540 >197509171242000 197509171242000 >197509171253240 197509171253240 >197509171305540 197509171305540 >197509171319180 197509171319180 >197509171329240 197509171336060 >197509171357240 197509171421240 >197509171436300 197509171751180 >197509171803060 197509171901180 >197509171920480 197509171920480 >197509171932180 197509171949300 >197509172003180 197509172026420 >197509172037420 197509172046000 >197509172102300 197509172119000 >197509172130000 197509172132420 >197509172144000 197509172144000 >197509172203060 197509172225060 >197509172237000 197509172244060 >197509172256300 197509172256300 >197509172324420 197509172324420 >197509172335180 197509172344540 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST
Unspecified
Unspecified
Navigation Data >Converted to time format with year at start. > >02/11/86 KAYE DUA0:[DATA.L475BS.N]L475BS.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >
19960119
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
Gravity Data >10/31/1998 /tiger/l/l475bs/grav/l-4-75-bs.160_050 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >05/02/86 CLINT DUA0:[DATA.L475BS]L475BS.160; >DRB0:[CLINT]REFMTJCGRV.EXE; >from JChilds l475bs.sm_grv file. > >Input was... >Converted to time format with year at start. > >02/11/86 KAYE DUA0:[DATA.L475BS.N]L475BS.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 > >time, lat, long, time(sec) to nearest nav fix, data values
19981031
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
Magnetics Data >06/20/2012 carolyn l-4-75-bs.220_050 > >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/l475bs/mag/l-4-75-bs.200_050 >/bear/programs/edit/automerge/automerge > >Converted to time format with year at start. > >05/15/86 CAROLYN DRS$DATA:[LEE75]L475BS.200; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 > >02/14/86 CAROLYN DRS$DATA:[L475BS.M]L475BS.240; >DUA0:[DATA.][L475BS.M]TEMP.EXE; >was L475BS._.MAGSX2 on TAM157 >was L475BS200.DAT on VAM157 > >Converted to time format with year at start. > >02/11/86 KAYE DUA0:[DATA.L475BS.N]L475BS.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 > >time, lat, long, time(sec) to nearest nav fix, data values
20120620
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
Bathymetry Data >10/31/1998 /tiger/l/l475bs/bath/l-4-75-bs.335_050 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >02/19/86 BECKIE DISK$USERDISK:[BECKIE.TEMP]L475BS.335; >DRB0:[DRS.BAT]BATRED.EXE;1 >This file was reduced using 1500m/sec as velocity >of sound in water (2-way). > >02/19/86 BECKIE DISK$USERDISK:[BECKIE.TEMP]L475BS.310; >DRB0:[DRS.NGDC]UNREFNGDC.EXE; >This file is hand-digetized bathy in 2-way traveltime(secs). > >Input was... >Converted to time format with year at start. > >02/11/86 KAYE DUA0:[DATA.L475BS.N]L475BS.050; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 > >time, lat, long, time(sec) to nearest nav fix, data values
19981031
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
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.
20120620
U.S. Geological Survey (USGS), Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.
20170201
U.S. Geological Survey
Alan O. Allwardt
Contractor -- Information Specialist
mailing and physical address
2885 Mission Street
Santa Cruz
CA
95060
831-460-7551
831-427-4748
aallwardt@usgs.gov
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
20201019
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Bering Sea, Aleutian Basin, Alaska
Point
Point
0.000001
0.000001
Decimal degrees
D_WGS_1984
WGS_1984
6378137.000000
298.25722210100002
l475bs.m77t
MGD77T single-beam bathymetry datasingle-beam bathymetry, gravity, and magnetics data file for L475BS
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
NGDC
This identifier varies in format and is supplied by the contributing organization
TIMEZONE
Time-zone correction
NGDC
In our datasets, no correction was applied. All values equal 0.
DATE
YYYYMMDD
NGDC
19750907
19750918
Year, month, day
TIME
Time
NGDC
0
2359
hours and decimal minutes
LAT
Latitude
World Geodetic System 1984 Geographic Coordinate System
54.02090
57.21860
decimal degrees
LON
Longitude
World Geodetic System 1984 Geographic Coordinate System
-169.05780
-165.50410
decimal degrees
POS_TYPE
Indicates how lat/lon was obtained
NGDC
1
3
1 = observed fix, 3 = interpolated fix, nil = unspecified
BAT_TTIME
Bathymetry, 2-way travel time
U.S. Geological Survey
0.093
3.047
seconds
CORR_DEPTH
Bathymetry, corrected depth
U.S. Geological Survey
69.8
2253.1
decimal meters
BAT_CPCO
Bathymetric Correction code - details the procedure used for determining the sound velocity correction to depth
NGDC
63
63
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
NGDC
1
3
1 - Observed, 3 - Interpolated (Header Seq. 12), 9 - Unspecified
MAG_TOT
Magnetics total field - 1st sensor
NGDC
49741.1
52855.6
gammas
MAG_RES
Magnetics residual field field
NGDC
-719.7
1043.1
gammas
GRA_OBS
Observed gravity
NGDC
981396.4
981725.2
milligals
EOTVOS
EOTVOS correction - E = 7.5 V cos(phi) * sin(alpha) + 0.0042 V*V
NGDC
-21.7
42
milligals
FREEAIR
Free-air Anomaly = G(observed) minus G(theoretical)
NGDC
-6.5
117.3
milligals
LINEID
LINE/TRACK/SEGMENT ID
NGDC
1
06B
Used, for example, to cross
reference with seismic data.
POINTID
SEISMIC SHOT-POINT NUMBER/POINT ID
NGDC
0
4437
Used, for example, to cross
reference with seismic data.
Bathymetry, gravity, magnetic, and navigation data for U.S. Geological Survey bathymetry survey L475BS in MGD77T format.
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.
U.S. Geological Survey
mailing and physical address
345 Middlefield Road MS 999
Menlo Park
CA
94025
USA
(650) 329-5078
(650) 329-5190
Downloadable Data
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.
MGD77t
10
MGD77
tab-delimited ASCII text files.
.645
http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l475bs/mgd77/
Data are available for download on the World Wide Web (WWW).
None
20201019
Gregory K. Miller
U.S. Geological Survey
Physical Scientist
mailing and physical address
U.S. Geological Survey, 600 Fourth Street South
St. Petersburg
FL
33701
USA
(727) 803-8747, ext. 3020
gmiller@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998