MGD77INFO

mgd77info − Get information about MGD77[+] files

mgd77info NGDC-ids [ −C[m|e] ] [ −E[m|e] ] [ −Hf|r ] [ −Iignore ] [ −V ]

mgd77info reads <legid>.[mgd77|nc] files and produces a single record of information about each cruise specified. The information includes beginning and end times, total track distances in km, longitude and latitude range, and the total number of geophysical observations. Optionally, choose instead to see the original MGD77 header section or its individual members.
If you need to know which tracks are crossing through a given region and what kinds of geophysical observations are available, consider using the x2sys tools to set up a tracks index data base (see x2sys_init for more information).

NGDC-ids

Can be one or more MGD77 8-character cruise identifiers. To give a list of names, use ‘cat cruises.lis‘. The ".mgd77" or ".nc" extensions will automatically be appended, if needed (use −I to ignore certain file types). Cruise files will be looked for first in the current directory and second in all directories listed in $MGD77_HOME/mgd77_paths.txt [If $MGD77_HOME is not set it will default to $GMTHOME/share/mgd77].

No space between the option flag and the associated arguments.

−C

List abbreviations for all columns present in the MGD77[+] files. Append m or e to limit the display to the MGD77 standard or MGD77+ extended set only.

−E

Give a one-line summary for each cruise listed.

−H

List the header and (if present) the MGD77+ history for each cruise. Append f to list individual parameters and their values, one entry per output line, in a format that can be searched using standard UNIX text tools, or r to see the raw, punchcard-formatted MGD77 original header block.

−I

Ignore certain data file formats from consideration. Append a|c|t to ignore MGD77 ASCII, MGD77+ netCDF, or plain tab-separated ASCII table files, respectively. The option may be repreated to ignore more than one format. [Default ignores none].

−V

Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].

To get one-line summary information about the cruises 01010047.mgd77 and 01010008.mgd77, try

mgd77info 01010047 01010008 −E > listing.lis

To see the original raw MGD77 header for cruise 01010047.mgd77, run

mgd77info 01010047 −Hr

To determine the Magnetic sampling rate used during cruise 01010047.mgd77, run

mgd77info 01010047 −Hf | grep "Magnetics Sampling Rate"

To see all the columns that the MGD77+ cruise 01010047.nc contains, run

mgd77info 01010047.nc −C

mgd77list(l), mgd77manage(l), mgd77path(l), mgd77track(l) x2sys_init(l)

Wessel, P., and W. H. F. Smith, 2005, The Generic Mapping Tools (GMT) version 4.1 Technical Reference & Cookbook, SOEST/NOAA.
Wessel, P., and W. H. F. Smith, 1998, New, Improved Version of Generic Mapping Tools Released, EOS Trans., AGU, 79 (47), p. 579.
Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released, EOS Trans., AGU, 76 (33), p. 329.
Wessel, P., and W. H. F. Smith, 1995, New Version of the Generic Mapping Tools Released, http: American Geophysical Union.
Wessel, P., and W. H. F. Smith, 1991, Free Software Helps Map and Display Data, EOS Trans., AGU, 72 (41), p. 441.
The Marine Geophysical Data Exchange Format - "MGD77", see http: