NAME

       grdedit - Modifying the header in a 2-D grdfile

SYNOPSIS

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

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

       -A     If necessary, adjust the file's x_inc, y_inc to be compatible with its domain (or a
              new  domain  set  with -R).  Older gridfiles (i.e., created prior to GMT 3.1) often
              had excessive slop in' x_inc, y_inc and an adjustment is necessary. Newer files are
              created correctly.

       -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.   The  new  w/e/s/n
              values will replace those in the grid, and the x_inc, y_inc values are adjusted, if
              necessary.

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

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

EXAMPLES

       Let us assume the file data.grd covers the area  300/310/10/30.  We  want  to  change  the
       boundaries  from  geodetic  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

       The  file  junk.grd was created prior to GMT 3.1 with incompatible -R and -I arguments. To
       reset the x- and y-increments we run

       grdedit junk.grd -A

SEE ALSO

       gmt(1gmt), grd2xyz(1gmt), xyz2grd(1gmt)

                                            1 Jan 2004                                 GRDEDIT(l)