THE MARINE GEOPHYSICAL DATA EXCHANGE FORMAT This newest revision makes the MGD77 format “Year 2000 Compliant”, ensuring it's success into 21st Century. The complete description of the MGD77 record format is available. GENERAL DESCRIPTION The digital format presented, and referred to as “MGD77”, is an exchange format for marine geophysical data (bathymetry, magnetics, and gravity) It is intended to be used for the transmission of data to and from a data center and may be useful for the exchange of data between marine institutions. Data is to be exchanged in files, one file per survey operation. Generally each survey operation is a port-to-port operation of a survey vessel, but in some cases several port-to-port operations of the same vessel are combined in single survey operation, especially if this is the manner of organizing the data at the contributing institution. Data may be exchanged via the Internet or on various mass storage devices such as 8mm or 9 track tapes, removable disks. The National Geophysical Data Center uses CD-ROM disks as its chief method of distribution of these data. SPECIAL VERSION - TRUNCATED MGD77 DATA RECORD GRAVITY DATA ONLY ASCII FORMAT DESCRIPTION
NOTE: Where there are no data values for bathymetry or gravity, those fields are filled with 9's. (e.g. bathymetry corrected depth = “999999”, observed gravity = “999999”, free-air anomaly = “9999”) BINARY FORMAT DESCRIPTION Data are stored on the CD-ROM in binary form.
NOTE: Where there are no data values for bathymetry or gravity, those fields are filled with 9's. (e.g. bathymetry corrected depth = “999999”, observed gravity = “999999”, free-air anomaly = “9999”) National Geophysical Data Center NOAA, E/GC3 325 Broadway Boulder, CO 80303-3328 TELEX: 592811 NOAA MASC BDR FAX: (303) 497-6513
Return to the Top of this Document Return to Gravity 1999 |