Survey Identifier: TBD375
Format Acronym: MGD77
Data Center File Number: 71020006
Parameters Surveyed Code: 55111
File Creation Date (yyyymmdd): 19891019
Source Institution: SOUTH AFRICAN GEOLOGICAL SURVEY
Country: SOUTH AFRICA
Platform Name: THOMAS B DAVIE
Platform Type Code: 1
Platform Type: SHIP
Chief Scientist(s): NO INFN
Project: TRACK NUMBERS 598-607.
Funding: NO INFN
Survey Departure Date (yyyymmdd): 19780303
Survey Arrival Date (yyyymmdd): 19780326
Navigation Instrumentation: NO INFN
Geodetic Datum/Position: NO INFN
Bathymetry Instrumentation: NO INFN
Additional Forms of Bathymetric Data: DIGITAL
Magnetics Instrumentation: NO INFN
Additional Forms of Magnetics Data: DIGITAL
Gravity Instrumentation: NONE
Seismic Instrumentation: NONE
Formats of Seismic Data: NONE
Topmost Latitude of Survey: +17
Bottommost Latitude: +05
Leftmost Longitude: +116
Rightmost Longitude: +122
General Digitizing Rate of Bathymetry: 050
Interpolation Scheme: NO INFN
General Digitizing Rate of Magnetics: 050
Reference Field Code: 88
Reference Field: DGRF-75
Method of Applying Residual Field: SEE BELOW.
Additional Documentation: *DATA QUALITY IS HIGHLY SUSPECT.* NAV:ASSUMED NE QUADRANT DESPITE GEBCO DIFF'S, & TRACKS CROSSING ISLANDS.(NW,SW QUAD'S HAVE NO SHALLOW AREAS;SE QUADRANT HAS, GREATER RELIEF.) BATH:ASSUMED UNC.MTRS. MAG:20,000 NANOTESLA RANGE IS HIGHLY, SUSPECT;COULD NOT CORRECT USING DGRF75. METHOD OF MAGNETICS CORRECTION USED:, ADDED 20,000 TO RAW TOTAL FIELD TO BRING VALUES UP TO 40,000N. THEN APPLIED, DGRF75 CORR. THE RESULTING RESIDUAL MAGNETIC ANOMALIES WERE THEN CENTERED, AROUND ZERO, USING AN OFFSET OF -2700 NANOTESLAS.(SKS/THD/HIG)
Number of Data Records: 4751
Min/Max Data Record:
Date: 1978 03 03
Latitude: +5.70167
Longitude: +116.64333
Bathymetry, 2- Way Traveltime: 000800
Bathymetry, Corrected Depth: 60.0
Magnetics Total Field, 1st Sensor: 221990
Magnetics Residual Field: -06278
Min/Max Data Record:
Date: 1978 03 26
Latitude: +16.02000
Longitude: +121.83000
Bathymetry, 2- Way Traveltime: 070130
Bathymetry, Corrected Depth: 5390.0
Magnetics Total Field, 1st Sensor: 239980
Magnetics Residual Field: +06220