mgd77convert (1) Linux Manual Page
mgd77convert – Convert MGD77 data to other file formats
Synopsis
mgd77convert NGDC-ids a|c|m |t [+]a|c|m|t [ ] [ ] [ [w][e][+] ] [ [level] ] Note: No space is allowed between the option flag and the associated arguments.
Description
mgd77convert reads versions of MGD77 files and writes the same data in (probably) another format to a new file in the current directory. Both pre- and post-Y2K MGD77 formats can be processed.Required Arguments
- NGDC-ids
- Can be one or more of five kinds of specifiers:
- 1.
- 8-character NGDC IDs, e.g., 01010083, JA010010etc., etc.
- 2.
- 2-character <agency> codes which will return all cruises from each agency.
- 3.
- 4-character <agency><vessel> codes, which will return all cruises from those vessels.
- 4.
- =<list>, where <list> is a table with NGDC IDs, one per line.
- 5.
- If nothing is specified we return all cruises in the data base.
(See mgd77info -L for agency and vessel codes). 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 $GMT_SHAREDIR/mgd77].
- -Fa|c|m |t
- Specifies the format of the input (From) files. Choose from a for standard MGD77 ASCII table (with extension .mgd77), c for the new MGD77+ netCDF format (with extension .nc), m for the new MGD77 t format (extension .m77t) and t for a plain ASCII tab-separated table dump (with extension .dat). Use -FC to recover the original MGD77 setting from the MGD77+ file [Default will apply any E77 corrections encoded in the file].
- -T[+]a|c|m |t
- Specifies the format of the output (To) files. Choose from a for standard MGD77 ASCII table (with extension .mgd77), c for the new MGD77+ netCDF format (with extension .nc), m for the new MGD77 t format (extension .m77t) and t for a plain ASCII tab-separated table dump (with extension .dat). We will refuse to create the file(s) if they already exist in the current directory. Prepend + to override this policy.
Optional Arguments
- -C
- Convert from NGDC two-file data sets *.h77, *.a77 to single file *.mgd77. No other options (except -V) are allowed. Give one or more names of *.h77 files, *.a77 files, or just the file prefixes.
- -D
- By default, the storage types used in a MGD77+ netCDF file greatly exceed the precision imposed by the ASCII MGD77 format. However, for the five items faa, eot, mag, diur and msd we use 2-byte integers with implied precisions of 0.1 mGal, 0.1 nTesla, and 1 m as in the MGD77 format. It is possible that at some point these items will need to be stored as 4-byte ints which would allow precisions of 10 fTesla, 1 nGal, and 0.01 mm, respectively. This option activates such storage [Default uses 2-byte integers].
- -L[w][e][+]
- Set the level of verification reporting [none] and where to send such reports [stderr]. Append a combination of w for warnings, e for errors, and + to send such log information to stdout.
- -V[level] (more …)
- Select verbosity level [c].
- -^ or just –
- Print a short message about the syntax of the command, then exits (NOTE: on Windows use just –).
- -+ or just +
- Print an extensive usage (help) message, including the explanation of any module-specific option (but not the GMT common options), then exits.
- -? or no arguments
- Print a complete usage (help) message, including the explanation of options, then exits.
- –-version
- Print GMT version and exit.
- –-show-datadir
- Print full path to GMT share directory and exit.
Examples
To convert a large set of a77,h77 pairs to proper mgd77 files, try
gmt mgd77convert -C *.h77To convert 01010047.mgd77 and 01010008.mgd77 to new netCDF .nc files, and capture all verification messages, try
gmt mgd77convert 01010047 01010008 -Fa -Tc -V -Lew+ > log.lisTo convert 01010047.nc back to MGD77 ASCII and make sure it is identical to the original file, try (Bourne shell syntax)
orig=`gmt mgd77path 01010047 -Ic`To convert 01010047.nc to a plain ASCII table for manual editing, overwriting any existing table, try
gmt mgd77convert 01010047 -Fc -Ta -V
diff $orig 01010047.mgd77
gmt mgd77convert 01010047 -Fc -T+t -VTo recover the original NGDC MGD77 version of 01020051.nc and ignore any E77 corrections, use
gmt mgd77convert 01020051 -FC -Ta -V