Survey Identifier: HT93T302

Format Acronym: MGD77
Data Center File Number: J1010070
Parameters Surveyed Code: 55500
File Creation Date (yyyymmdd): 19980123
Source Institution: HYDROGRAPHIC DEPARTMENT
Country: JAPAN
Platform Name: TAKUYO
Platform Type Code: 1
Platform Type: SHIP
Chief Scientist(s): SHIGERU KASUGA
Project: 30TH AREA CONTINENTAL SHELF SURVEY (HEISEI5-FOURTH)
Funding: HYDROGRAPHIC DEP
Survey Departure Date (yyyymmdd): 19931102
Port of Departure: TOKYO,JAPAN
Survey Arrival Date (yyyymmdd): 19931119
Port of Arrival: TOKYO,JAPAN
Navigation Instrumentation: GPS/LORAN-C
Geodetic Datum/Position: INTEGRATED NAVIGATION SYSTEM
Bathymetry Instrumentation: SEA-BEAM BATHYMETRIC SYSTEM 12KHZ
Magnetics Instrumentation: PROTON MAGUNETMETER (PMM-100)
Gravity Instrumentation: ONBOARD GRAVIMETER SYSTEM (GMBH KSS-30)
Topmost Latitude of Survey: +21
Bottommost Latitude: +18
Leftmost Longitude: +137
Rightmost Longitude: +141
General Digitizing Rate of Bathymetry: 10
Assumed Sound Velocity: 1500
Bathymetric Datum Code: 05
General Digitizing Rate of Magnetics: 10
General Sampling Rate of Magnetics: 60
Magnetic Sensor Tow Distance: 252
Reference Field Code: 88
Reference Field: IGRF1990
General Digitizing Rate of Gravity: 10
General Sampling Rate of Gravity: 5
Theoretical Gravity Formula Code: 3
Theoretical Gravity Formula: r1967
Reference System: JGSN75
Corrections Applied: DRIFT & EOTVOS CORRECTION
Departure Base Station Gravity: -8702
Departure Base Station Description: JHDGO(TOKYO PORT)
Arrival Base Station Gravity: -8700
Arrival Base Station Description: JHDGO(TOKYO PORT)
Additional Documentation: Corection for sound velocity was applied to the seabeam data using tables for, the area No.53 in Echo-sounding Correction Tables NP 139 (Hydrographic Dept. UK,1980). The correction for time variations were carried out with the geomagnetic, variations at the Titisima data of Magnetic Observatory,JMA.
Number of Data Records: 931

Min/Max Data Record:
Date: 1993 11 05
Latitude: +18.04250
Longitude: +137.46384
Bathymetry, Corrected Depth: 3530.0
Magnetics Residual Field: -02190
Free-Air Anomaly: -0650

Min/Max Data Record:
Date: 1993 11 16
Latitude: +21.00050
Longitude: +140.00984
Bathymetry, Corrected Depth: 6950.0
Magnetics Residual Field: +00760
Free-Air Anomaly: +0550