grdcut - Extract a subregion out of a . grd file grdcut input _ file . grd -G output _ file . grd -R west / east / south / north [ r ] [ -V ] grdcut will produce a new output _ file . grd file which is a subregion of input _ file . ... The subregion is specified with -R west / east / south / north as in other programs; the specified range must not exceed the range of input _ file . ... grd this is the input . grd format file. G output _ file . grd this is the output . ...