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)