Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Originator: Coastal and Marine Geology Program Publication_Date: 2013 Title: l781wg.m77t - MGD77 data file for Geophysical data from field activity L-7-81-WG in Western Gulf of Alaska from 06/11/1981 to 06/30/1981 Geospatial_Data_Presentation_Form: tab-delimited ASCII text files Publication_Information: Publication_Place: Menlo Park, CA Publisher: U.S. Geological Survey Online_Linkage: http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l781wg/mgd77/ Larger_Work_Citation: Citation_Information: Originator: Wm. Clinton Steele Originator: Carolyn H. Degnan Originator: Gary B. Deeter Originator: Jean A. Riordan Publication_Date: 1980 Title: DESCRIPTION OF MARINE GEOPHYSICAL DATA COLLECTED BY THE U.S. GEOLOGICAL SURVEY AND HOW TO OBTAIN IT Edition: 1.0 Geospatial_Data_Presentation_Form: Digital Document Series_Information: Series_Name: U.S. Geological Survey Open File Report Issue_Identification: 167 Publication_Information: Publication_Place: Menlo Park, CA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/1989/0167/report.pdf Description: Abstract: Single-beam bathymetry, gravity, and magnetic data along with transit satellite navigation data was collected as part of field activity L-7-81-WG in Western Gulf of Alaska from 06/11/1981 to 06/30/1981,http://walrus.wr.usgs.gov/infobank/l/l781wg/html/l-7-81-wg.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/l781wg/html/l-7-81-wg.bath.html http://walrus.wr.usgs.gov/infobank/l/l781wg/html/l-7-81-wg.grav.html and http://walrus.wr.usgs.gov/infobank/l/l781wg/html/l-7-81-wg.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. Purpose: 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/ ). 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19810611 Ending_Date: 19810630 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -155.55890 East_Bounding_Coordinate: -146.07220 North_Bounding_Coordinate: 59.95458 South_Bounding_Coordinate: 55.79541 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:607e8869-001f-4ef5-9cfc-7513774ab7ce Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificinformation Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Marine Geology Theme_Keyword: Marine Geophysics Theme_Keyword: Single-beam Bathymetry Theme_Keyword: Water Depth Theme_Keyword: Seafloor Topography Theme_Keyword: Marine Seismic Theme_Keyword: Marine Gravity Theme_Keyword: Marine Magnetics Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: distributions Theme_Keyword: bathymetry and elevation Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: single-beam echo sounder Theme_Keyword: gravimetry Theme_Keyword: magnetic field observations Theme_Keyword: marine geophysics Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: single-beam echo sounder Theme_Keyword: bathymetry measurement Theme_Keyword: bathymetry Theme_Keyword: gravimeter measurement Theme_Keyword: magnetometer measurement Theme_Keyword: marine geophysics Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Western Gulf of Alaska Place_Keyword: USA Place: Place_Keyword_Thesaurus: NGA GEOnet Names Server (GNS) Place_Keyword: Bay of Campeche 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. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Gregory K. Miller Contact_Organization: U.S. Geological Survey Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747, ext. 3020 Contact_Electronic_Mail_Address: gmiller@usgs.gov Data_Set_Credit: Roland Von Huene (Chief Scientist) Cross_Reference: Citation_Information: Originator: Hittelman, Allen M., Groman, Robert C., Haworth, Richard T., Holcombe, Troy L., McHendrie, Graig, Smith, Stuart M., and Metzger, Dan R. Publication_Date: 2010 Title: The marine geophysical data exchange format - MGD77 / MGD77T Publication_Information: Publication_Place: Boulder, CO Publisher: National Geophysical Data Center, National Oceanic and Atmospheric Administration Other_Citation_Details: 25 p. Online_Linkage: http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.pdf Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: 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. Logical_Consistency_Report: 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. Completeness_Report: Start and end date/times of data >Navigation Data (l-7-81-wg.053 [SINS]) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198106111308570 198106291228340 >198106291251500 198106301844000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Gravity Data (l-7-81-wg.162_053) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198106111311000 198106122017400 >198106122037200 198106130309400 >198106130315200 198106131402000 >198106131421400 198106141229300 >198106141245060 198106152314360 >198106152320280 198106170053240 >198106170102440 198106171251200 >198106171257520 198106172123320 >198106172132040 198106181429000 >198106181658080 198106190953360 >198106191002080 198106201139320 >198106201145320 198106210430360 >198106210437560 198106211305120 >198106211311040 198106212136200 >198106212143240 198106221526480 >198106221537330 198106241218520 >198106241905520 198106250331560 >198106250338560 198106261547040 >198106261552560 198106270020560 >198106270027120 198106280404360 >198106280410000 198106282058400 >198106282103480 198106291554280 >198106291601000 198106300049400 >198106300057360 198106301844000 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Magnetics Data (l-7-81-wg.220_053) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198106111617200 198106112250430 >198106121001200 198106121356280 >198106121606000 198106121808120 >198106131911000 198106141232300 >198106141248060 198106152317520 >198106152323280 198106170056360 >198106170105440 198106171254280 >198106171300520 198106172126440 >198106172135040 198106181432000 >198106181701080 198106190956520 >198106191005080 198106201143240 >198106201148320 198106210434280 >198106210440560 198106211308280 >198106211314040 198106212139400 >198106212146240 198106221530400 >198106221540330 198106241222080 >198106241908520 198106250335160 >198106250341560 198106260402080 >198106260607400 198106261550400 >198106261555560 198106270024080 >198106270030120 198106270227160 >198106270636000 198106280407560 >198106280413000 198106290320520 >198106290507400 198106291558240 >198106291604000 198106300053240 >198106300100360 198106301103100 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Bathymetry Data (l-7-81-wg.336_053) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198106111455000 198106112003360 >198106112015540 198106122358120 >198106130130000 198106132313120 >198106132324120 198106150618000 >198106150730000 198106151247360 >198106151300000 198106160049300 >198106160100000 198106200349540 >198106200402180 198106200430000 >198106200448120 198106201218480 >198106201237420 198106201332240 >198106201351120 198106210430480 >198106210445180 198106210719180 >198106210731120 198106210731120 >198106210742480 198106210746480 >198106210803540 198106210818000 >198106210832360 198106211630000 >198106211643480 198106221457540 >198106221508360 198106221702060 >198106221714360 198106221744000 >198106221758120 198106230205540 >198106230216480 198106230233180 >198106230245360 198106230351120 >198106230411540 198106230641360 >198106230710060 198106232306480 >198106232326180 198106240518360 >198106240530060 198106240705480 >198106240716360 198106241444480 >198106241520000 198106241700000 >198106241715000 198106241829120 >198106241901000 198106242033240 >198106242057180 198106242059180 >198106242120240 198106250440120 >198106250452060 198106252152360 >198106252222420 198106252315360 >198106260002540 198106260002540 >198106260053540 198106260147180 >198106260200000 198106261726000 >198106261736540 198106262147240 >198106262202360 198106270241300 >198106270301060 198106270412360 >198106270429540 198106271433000 >198106271447300 198106272139300 >198106272153060 198106272209240 >198106272224120 198106280018420 >198106280029120 198106280300000 >198106280310240 198106280625540 >198106280637360 198106280958120 >198106281014480 198106281226120 >198106281238000 198106281609480 >198106281637060 198106281909000 >198106281935480 198106282301240 >198106282315240 198106290133420 >198106290205240 198106290751480 >198106290821120 198106290900000 >198106290912120 198106292313360 >198106292323420 198106301241540 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >Seismic Shots Data (l-7-81-wg.421_053) >YYYYMMDDHHMMSST YYYYMMDDHHMMSST >198106132000200 198106140244480 >198106141057160 198106141442560 >198106141950350 198106142333010 >198106150044280 198106150211340 >198106150311160 198106150748290 >198106151003220 198106151611160 >198106151616380 198106151616380 >198106151621420 198106151851070 >198106151933280 198106152037230 >198106152042300 198106162132160 >198106162359530 198106170608090 >198106170818100 198106171100160 >198106171141350 198106180714110 >198106180824270 198106181404200 >198106190321160 198106191645000 >198106191752560 198106191902560 >198106192045550 198106201824330 >198106202113580 198106211912270 >198106212012450 198106212233540 >198106212341320 198106222015130 >198106222117480 198106222340390 >198106230046460 198106231309000 >198106231326270 198106231915080 >198106232017040 198106240945060 >198106241223430 198106251048550 >198106251218200 198106260352510 >198106270920400 198106272057120 >198106272154210 198106272239430 >198106272323430 198106280432080 >198106280518560 198106280724460 >198106280858320 198106281600080 >198106281642010 198106281902360 >198106281937300 198106282205330 >198106282211250 198106282211250 >198106282216590 198106290320370 >198106290621540 198106291402500 >198106291505100 198106291706510 >198106291739090 198106292117270 >YYYYMMDDHHMMSST YYYYMMDDHHMMSST Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Unspecified Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Unspecified Lineage: Process_Step: Process_Description: Navigation Data >Converted to time format with year at start. > >07/23/85 KAYE DRS$DATA:[L781WG.N]L781WG.053; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l781wg.sinsd1._. > Process_Date: 19960119 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey (USGS) http://www.usgs.gov, Coastal and Marine Geology (CMG) http://walrus.wr.usgs.gov Contact_Person: Clint Steele http://walrus.wr.usgs.gov/staff/csteele.html Contact_Position: InfoBank Group Leader http://walrus.wr.usgs.gov/staff/csteele.html Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5055 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: infobank@octopus.wr.usgs.gov Process_Step: Process_Description: Gravity Data >10/31/1998 /tiger/l/l781wg/grav/l-7-81-wg.162_053 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >04/25/88 BECKIE DUA0:[DATA.L476WG]L781WG.162; >DUA0:[DRS.GRV]GRAVRED.EXE;4 >Free Air Anomaly data > >*10/15/85 BARB USR$DISK:[DRS.DATA.L781WG.G]L781WG.140; >USR$DISK:[DRS.REFMT}REFORMAT.EXE; > >*10/11/85 BARB DRS$DATA:[L781WG.G]L781WG.111; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 > >*04/18/88 BECKIE DUA0:[DATA.L476WG]L781WG.070; >DUA0:[DRS.NAV]EOTCSSP.EXE;1 >Eotvos/course/speed/distance data > >07/23/85 KAYE DRS$DATA:[L781WG.N]L781WG.053; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l781wg.sinsd1._. > >Input was... >Converted to time format with year at start. > >07/23/85 KAYE DRS$DATA:[L781WG.N]L781WG.053; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l781wg.sinsd1._. > >time, lat, long, time(sec) to nearest nav fix, data values Process_Date: 19981031 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG) Contact_Person: Clint Steele Contact_Position: InfoBank Group Leader Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5055 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: infobank@octopus.wr.usgs.gov Process_Step: Process_Description: Magnetics Data >06/20/2012 carolyn l-7-81-wg.220_053 > >Reprocessed using subroutines from Susan Macmillan's >IGRF SYNTHESIS PROGRAM >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/l781wg/mag/l-7-81-wg.200_053 >/bear/programs/edit/automerge/automerge > >01/21/97 clint l-7-81-wg.200 >/bear/programs/refmt/vms2unix/vms2unix >Raw magnetics data > >11/19/85 CAROLYN DRS$DATA:[L781WG.M]L781WG.200; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >was L781WG._.MAGSB1 on TAM287 >was L781WG221.DAT on VAM287 > >Converted to time format with year at start. > >07/23/85 KAYE DRS$DATA:[L781WG.N]L781WG.053; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l781wg.sinsd1._. > >time, lat, long, time(sec) to nearest nav fix, data values Process_Date: 20120620 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG) Contact_Person: Clint Steele Contact_Position: InfoBank Group Leader Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5055 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: infobank@octopus.wr.usgs.gov Process_Step: Process_Description: Bathymetry Data >10/31/1998 /tiger/l/l781wg/bath/l-7-81-wg.336_053 >/bear/programs/edit/automerge/automerge > >Input was... >Converted to time format with year at start. > >01/13/86 BECKIE DISK$USERDISK:[BECKIE.BAT360]L781WG.335; >DRB0:[DRS.BAT]BATRED.EXE;1 >This file was hadn-digetized in 2-way traveltime(secs). >It was reduced using no Matthews correction and vel- >ocity of sound assumed was 1500m/sec. > >Input was... >Converted to time format with year at start. > >07/23/85 KAYE DRS$DATA:[L781WG.N]L781WG.053; >DRB0:[DRS.REFMT]REFORMAT.EXE;4 >Original file name is l781wg.sinsd1._. > >time, lat, long, time(sec) to nearest nav fix, data values Process_Date: 19981031 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey (USGS), Coastal and Marine Geology (CMG) Contact_Person: Clint Steele Contact_Position: InfoBank Group Leader Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5055 Contact_Facsimile_Telephone: (650) 329-5190 Contact_Electronic_Mail_Address: infobank@octopus.wr.usgs.gov Process_Step: Process_Description: 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. Process_Date: 20120620 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey (USGS), Coastal and Marine Geology (CMG) Contact_Person: Carolyn H. Degnan Contact_Position: Geophysicist Contact_Address: Address_Type: mailing and physical address Address: USGS Pacific Coastal & Marine Science Center, 400 Natural Bridges Drive City: Santa Cruz State_or_Province: CA Postal_Code: 95060-5792 Country: USA Contact_Voice_Telephone: (831) 460-7452 Contact_Facsimile_Telephone: (831) 427-4748 Contact_Electronic_Mail_Address: infobank@octopus.wr.usgs.gov Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20170201 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Process_Date: 20201019 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Indirect_Spatial_Reference: Western Gulf of Alaska Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: D_WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.25722210100002 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: l781wg.m77t Entity_Type_Definition: MGD77T single-beam bathymetry, gravity, and magnetics data file for U171GM Entity_Type_Definition_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. Attribute: Attribute_Label: SURVEY_ID Attribute_Definition: Survey identifier supplied by the contributing organization Attribute_Definition_Source: NGDC Attribute_Domain_Values: Unrepresentable_Domain: This identifier varies in format and is supplied by the contributing organization Attribute: Attribute_Label: TIMEZONE Attribute_Definition: Time-zone correction Attribute_Definition_Source: NGDC Attribute_Domain_Values: Unrepresentable_Domain: In our datasets, no correction was applied. All values equal 0. Attribute: Attribute_Label: DATE Attribute_Definition: YYYYMMDD Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 19810611 Range_Domain_Maximum: 19810630 Attribute_Units_of_Measure: Year, month, day Attribute: Attribute_Label: TIME Attribute_Definition: Time Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0 Range_Domain_Maximum: 2359.993 Attribute_Units_of_Measure: hours and decimal minutes Attribute: Attribute_Label: LAT Attribute_Definition: Latitude Attribute_Definition_Source: World Geodetic System 1984 Geographic Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 55.79541 Range_Domain_Maximum: 59.95458 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: LON Attribute_Definition: Longitude Attribute_Definition_Source: World Geodetic System 1984 Geographic Coordinate System Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -155.55889 Range_Domain_Maximum: -146.07226 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: POS_TYPE Attribute_Definition: Indicates how lat/lon was obtained Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 3 Attribute_Units_of_Measure: 1 = observed fix, 3 = interpolated fix, nil = unspecified Attribute: Attribute_Label: BAT_TTIME Attribute_Definition: Bathymetry, 2-way travel time Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.017 Range_Domain_Maximum: 7.217 Attribute_Units_of_Measure: seconds Attribute: Attribute_Label: CORR_DEPTH Attribute_Definition: Bathymetry, corrected depth Attribute_Definition_Source: U.S. Geological Survey Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 12.8 Range_Domain_Maximum: 5423.7 Attribute_Units_of_Measure: decimal meters Attribute: Attribute_Label: BAT_CPCO Attribute_Definition: Bathymetric Correction code - details the procedure used for determining the sound velocity correction to depth Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 63 Range_Domain_Maximum: 63 Attribute_Units_of_Measure: 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 Attribute: Attribute_Label: BAT_TYPCO Attribute_Definition: Bathymetry type code - indicates how the bathymetric value was obtained Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 3 Attribute_Units_of_Measure: 1 - Observed, 3 - Interpolated (Header Seq. 12), 9 - Unspecified Attribute: Attribute_Label: MAG_TOT Attribute_Definition: Magnetics total field - 1st sensor Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 53032 Range_Domain_Maximum: 56947.3 Attribute_Units_of_Measure: gammas Attribute: Attribute_Label: MAG_RES Attribute_Definition: Magnetics residual field field Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -1165.2 Range_Domain_Maximum: 2201.1 Attribute_Units_of_Measure: gammas Attribute: Attribute_Label: GRA_OBS Attribute_Definition: Observed gravity Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 981469.7 Range_Domain_Maximum: 981941.9 Attribute_Units_of_Measure: milligals Attribute: Attribute_Label: EOTVOS Attribute_Definition: EOTVOS correction - E = 7.5 V cos(phi) * sin(alpha) + 0.0042 V*V Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -46.1 Range_Domain_Maximum: 43.2 Attribute_Units_of_Measure: milligals Attribute: Attribute_Label: FREEAIR Attribute_Definition: Free-air Anomaly = G(observed) minus G(theoretical) Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -116.9 Range_Domain_Maximum: 131.2 Attribute_Units_of_Measure: milligals Attribute: Attribute_Label: LINEID Attribute_Definition: LINE/TRACK/SEGMENT ID Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 11 Range_Domain_Maximum: 122 Attribute_Units_of_Measure: Used, for example, to cross reference with seismic data. Attribute: Attribute_Label: POINTID Attribute_Definition: SEISMIC SHOT-POINT NUMBER/POINT ID Attribute_Definition_Source: NGDC Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 41 Range_Domain_Maximum: 5070 Attribute_Units_of_Measure: Used, for example, to cross reference with seismic data. Overview_Description: Entity_and_Attribute_Overview: Bathymetry, gravity, magnetic, and navigation data for U.S. Geological Survey survey l781wg 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. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Resource_Description: Downloadable Data Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: MGD77t Format_Version_Number: 10 Format_Specification: MGD77 Format_Information_Content: tab-delimited ASCII text files. Transfer_Size: 2.8 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://www.ngdc.noaa.gov/mgg/trk/trackline/samuel_p._lee/l781wg/mgd77/ Access_Instructions: Data are available for download on the World Wide Web (WWW). Fees: None Metadata_Reference_Information: Metadata_Date: 20201019 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Gregory K. Miller Contact_Organization: U.S. Geological Survey Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: U.S. Geological Survey, 600 Fourth Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747, ext. 3020 Contact_Electronic_Mail_Address: gmiller@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998