grdcut (1gmt)

grdcut input_file.grd -Goutput_file.grd -Rwest/east/south/north[r] [ -V ]

grdcut will produce a new output_file.grd file which is a subregion of input_file.grd. The subregion is specified with -Rwest/east/south/north as in other programs; the specified range must not exceed the range of input_file.grd. If in doubt, run grdinfo to check range. Complementary to grdcut there is grdpaste, which will join together two grdfiles along a common edge.

input_file.grd

this is the input .grd format file.

-Goutput_file.grd

this is the output .grd format file.

-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. This defines the subregion to be cut out.

-V

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

Suppose you have used surface to grid ship gravity in the region between 148E - 162E and 8N - 32N, and you do not trust the gridding near the edges, so you want to keep only the area between 150E - 160E and 10N - 30N, then:

grdcut grav_148_162_8_32.grd -Ggrav_150_160_10_30.grd -R150/160/10/30 -V

grdpaste(1gmt), grdinfo(1gmt), gmt(1gmt)