NAME

     grdedit - Modifying the header in a 2-D grdfile

SYNOPSIS

     grdedit               grdfile               [              -
     Dxunit/yunit/zunit/scale/offset/title/remark]       [      -
     Rwest/east/south/north[r] ] [-S ]

DESCRIPTION

     grdedit reads the header information in a binary 2-D grdfile
     and  replaces  the  information  with values provided on the
     command line [if any].  As an option,  global,  geographical
     grids  (with  360 degrees longitude range) can be rotated in
     the east-west direction.  grdedit  only  operates  on  files
     containing a grdheader.
          No space between the option  flag  and  the  associated
     arguments.   Use  upper  case for the option flags and lower
     case for modifiers.

     grdfile
          Name of the 2-D grdfile to modify

OPTIONS

     -D    Give  new  values  for  xunit,  yunit,  zunit,  scale,
          offset, title, and remark.  To leave some of the values
          untouched, specify = as the new value.

     -R    west, east, south, and north  specify  the  Region  of
          interest.  To specify boundaries in degrees and minutes
          [and seconds], use the dd:mm[:ss] format.  Append r  if
          lower  left  and  upper right map coordinates are given
          instead of wesn.

     -S    For global, geographical grids only.  Grid values will
          be shifted laterally according to the new borders given
          in -R.

EXAMPLES

     Let  us  assume  the   file   data.grd   covers   the   area
     300/310/10/30.   We  want to change the boundaries from geo-
     detic longitudes to geographic and put a new  title  in  the
     header.  We accomplish this by

     grdedit  data.grd  - R-60/-50/10/30   -  D=/=/=/=/=/"Gravity
     Anomalies"/=

     The grid world.grd has the limits  0/360/-72/72.   To  shift
     the data so that the limits would be -180/180/-72/72, use

     grdedit world.grd -R-180/180/-72/72 -S

SEE ALSO

     gmt, grd2xyz, xyz2grd

REFERENCES

     Wessel, P., and W. H. F. Smith, 1995,  The  Generic  Mapping
     Tools  (GMT)  version  3.0  Technical  Reference & Cookbook,
     SOEST/NOAA.
     Wessel, P., and W. H. F. Smith, 1995,  New  Version  of  the
     Generic Mapping Tools Released, EOS Trans. AGU, 76, 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, p. 441.