NAME

     gmtlist - A data-extractor for <legid>.gmt files


SYNOPSIS

     gmtlist leg-ids [ -Ccorrectionfile  ]  [  -Dastartdate  ]  [
     -Dbstopdate   ]   [   -Fflags   ]   [   -G   ]   [  -H  ]  [
     -Rwest/east/south/north ] [ -Sastartdist ] [ -Sbstopdist ] [
     -V ] [ -Wweight ] [ -b ]


DESCRIPTION

     gmtlist reads <legid>.gmt files and produces  an  ASCII  [or
     binary]  table.   The  <legid>.gmt  files  contain  time(s),
     latitude(y), longitude(x), gravity(g/G), magnetics(m/M), and
     bathymetry(t/T), and the user may extract any combination of
     these 6 parameters + distance(d), heading (h), velocity (v),
     and  weight  (w, see -W).  A sub-section can be specified by
     passing  time-  or  distance-intervals  along  track  or  by
     selecting a region.

     leg-ids
          Can be one or more  cruisenames.  To  give  a  list  of
          names, use `cat list_of_legs`.


OPTIONS

     No space between the option flag and  the  associated  argu-
     ments

     -C   Apply crossover Corrections to the data. If no  correc-
          tion  file  is given, gmtlist reads the default correc-
          tion file. (See XSYSTEM for how  to  set  up  your  own
          correction file)

     -Da  Do   not   list   data   collected   before   startdate
          (mm/dd/yyyy/hh:mm)  [Default is first day].

     -Db  Do   not   list   data   collected    after    stopdate
          (mm/dd/yyyy/hh:mm). [Default is last day].

     -F   Can be any combination of  syxgmtdhv  to  indicate  the
          desired  output data. The data will appear in the order
          indicated by flags. If GMT is substituted for gmt, only
          records  that have that combination of data are written
          out.  If  s  is  followed   by   c   (calender),   then
          yyyy/mm/dd/hh/mm/ss is written out, if s is followed by
          j  (julian),  then  yyyy/jd/hh/mm/ss  is  written  out.
          Default is seconds from start of year.

     -G   Force Geographical longitudes (-180/+180)  rather  than
          geodetic (0-360) [Default].

     -H   Issue a header record with names for each data field.

     -Sa  Do not list data that are less than startdist km  along
          track from port of departure. [Default is 0].

     -Sb  Do not list data that are more than stopdist  km  along
          track  from  port  of  departure. [Default is length of
          track].

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

     -W   Set the weight for these data.   Weight  output  option
          must  be  set in -F.  This is useful if the data are to
          be processed with  the  weighted  averaging  techniques
          offered by blockmean, blockmedian, and blockmode.

     -b   Selects  binary  output  mode  (in  double   precision)
          [Default  is  ASCII].  -H is ignored if -b is selected.
          Julian and calender dates are not supported for  binary
          time output (i.e., you get seconds from start of year).


EXAMPLES

     To get a (distance,  heading,  crossover-corrected  gravity,
     bathymetry)  listing from c2104.gmt, starting at June 3 1971
     20:45 and ending at distance = 5000 km,  use  the  following
     command:

     gmtlist c2104 -Da6/3/1971/20:45 -Sb5000 -Fdhgt -C > myfile

     To make input  for  blockmean  and  surface  using  all  the
     cruises  listed in the file gmt.list, but only the data that
     are inside the specified area, and make output binary, try:

     gmtlist  `cat   gmt.list`   -Fxyg   -R-40/-30/25/35   -b   >
     allgrav.xyg


SEE ALSO

     gmt(l), xsystem(l)


REFERENCES

     Wessel, P., and W. H. F. Smith, 1999,  The  Generic  Mapping
     Tools  (GMT)  version  3.2  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://www.agu.org/eos_elec/95154e.html, Copyright  1995  by
     the 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.