U.S. Geological Survey
Coastal and Marine Geology Program
2013
g178eg.m77t - MGD77 data file for Geophysical data from field activity G-1-78-EG in Eastern Gulf of Alaska, Glacier Bay from 09/12/1978 to 09/23/1978
tab-delimited ASCII text files
Menlo Park, CA
U.S. Geological Survey
http://www.ngdc.noaa.gov/mgg/trk/trackline/growler/g178eg/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 data along with DGPS navigation data was collected as part of field activity G-1-78-EG in Eastern Gulf of Alaska, Glacier Bay from 09/12/1978 to 09/23/1978, http://walrus.wr.usgs.gov/infobank/g/g178eg/html/g-1-78-eg.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/g/g178eg/html/g-1-78-eg.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.
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.
19780912
19780923
ground condition
None planned
-136.59869
-135.79955
59.05107
58.72551
USGS Metadata Identifier
USGS:dd57e21d-0ae9-4ea2-b8f2-3745ab1c0535
ISO 19115 Topic Category
geoscientificinformation
oceans
None
Marine Geology
Marine Geophysics
Bathymetry
Water Depth
Seafloor Topography
Data Categories for Marine Planning
distributions
bathymetry and elevation
Marine Realms Information Bank (MRIB) keywords
single-beam echo sounder
marine geophysics
USGS Thesaurus
single-beam echo sounder
bathymetry measurement
bathymetry
marine geophysics
Geographic Names Information System (GNIS)
AK
Eastern Gulf of Alaska
Eastern Gulf of Alaska, Glacier Bay
Glacier Bay, AK
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
Paul Carlson (Chief Scientist, USGS Western Region); Bruce Molnia (Chief Scientist, USGS Western Region)
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 (g-1-78-eg.051 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197809121522000 197809121745000 >197809121800000 197809121800000 >197809131031000 197809131200000 >197809161539002 197809161800002 >197809170835002 197809170852002 >197809171007002 197809171116002 >197809171127002 197809171154002 >197809171205002 197809171215002 >197809181548002 197809181735002 >197809191035002 197809191250002 >197809191423002 197809191634002 >197809211245002 197809211445002 >197809211637002 197809211807002 >197809220920002 197809220929002 >197809220940002 197809221000002 >197809221130002 197809221218002 >197809221555002 197809221647002 >197809221905002 197809222001002 >197809230930002 197809230945002 >197809231050003 197809231120003 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (g-1-78-eg.310_051) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >197809121522000 197809121659160 >197809121706020 197809121706030 >197809121712160 197809121722010 >197809121730050 197809121800000 >197809131031000 197809131200000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST
Unspecified
Unspecified
Navigation Data >Converted to time format with year at start. > >05/08/86 CAROLYN DRS$DATA:[REARIC]G178EG.051; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >255/1522-256/1200 from Doug Rearic >259/1539-266/1120 was G178EG.050 on DRS210 reformatted by Kaye >
19951206
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
Carolyn H. Degnan
Geophysicist
mailing and physical address
USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
USA
(831) 460-7452
(831) 427-4748
infobank@octopus.wr.usgs.gov
Bathymetry Data >10/31/1998 /tiger/g/g178eg/bath/g-1-78-eg.310_051 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >05/08/86 CAROLYN DRS$DATA:[REARIC]G178EG.310; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >travel times to SEAFLOOR (depth = travel_time * 750) >from Doug Rearic > >Input was... >Converted to time format with year at start. > >05/08/86 CAROLYN DRS$DATA:[REARIC]G178EG.051; >DRB0:[DRS.REFMT]REFORMAT.EXE;5 >255/1522-256/1200 from Doug Rearic >259/1539-266/1120 was G178EG.050 on DRS210 reformatted by Kaye > >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
Eastern Gulf of Alaska, Glacier Bay
Point
Point
0.000001
0.000001
Decimal degrees
D_WGS_1984
WGS_1984
6378137.000000
298.25722210100002
g178eg.m77t
MGD77T single-beam bathymetry data file for G178EG
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
19780912
19780923
Year, month, day
TIME
Time
NGDC
836
1955
hours and decimal minutes
LAT
Latitude
World Geodetic System 1984 Geographic Coordinate System
58.72552
59.05081
decimal degrees
LON
Longitude
World Geodetic System 1984 Geographic Coordinate System
-136.59869
-135.79956
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
0.06
0.572
seconds
CORR_DEPTH
Bathymetry, corrected depth
U.S. Geological Survey
45
423
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
Bathymetry and navigation data for U.S. Geological Survey bathymetry survey G178EG in MGD77T format.
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.
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.
.031
http://www.ngdc.noaa.gov/mgg/trk/trackline/growler/g178eg/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