NAME
grdcut - Extract a subregion out of a .grd file
SYNOPSIS
grdcut input_file.grd -Goutput_file.grd -Rwest/east/south/north[r] [ -V
] [ -f[i|o]colinfo ]
DESCRIPTION
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 xmin, xmax, ymin, and ymax specify the Region of interest. For
geographic regions, these limits correspond to west, east,
south, and north and you may specify them in decimal degrees or
in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
and upper right map coordinates are given instead of wesn. The
two shorthands -Rg -Rd stand for global domain (0/360 or
-180/+180 in longitude respectively, with -90/+90 in latitude).
For calendar time coordinates you may either give relative time
(relative to the selected TIME_EPOCH and in the selected
TIME_UNIT; append t to -JX|x), or absolute time of the form
[date]T[clock] (append T to -JX|x). At least one of date and
clock must be present; the T is always required. The date string
must be of the form [-]yyyy[-mm[-dd]] (Gregorian calendar) or
yyyy[-Www[-d]] (ISO week calendar), while the clock string must
be of the form hh:mm:ss[.xxx]. The use of delimiters and their
type and positions must be as indicated (however, input/output
and plotting formats are flexible). This defines the subregion
to be cut out.
OPTIONS
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-f Special formatting of input and output columns (time or geo-
graphical data) Specify i(nput) or o(utput) [Default is both
input and output]. Give one or more columns (or column ranges)
separated by commas. Append T (Absolute calendar time), t (time
relative to chosen TIME_EPOCH), x (longitude), y (latitude), g
(geographic coordinate), or f (floating point) to each column or
column range item.
EXAMPLES
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
SEE ALSO
grdpaste(l), grdinfo(l), gmt(l)
GMT4.0 1 Oct 2004 GRDCUT(l)
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