grdclip(1) GMT grdclip(1)
NAME
grdclip - Clip the range of grids
SYNOPSIS
grdclip ingrid -Goutgrid [ -Rregion ] [ -Sahigh/above ] [
-Sblow/below ] [ -Silow/high/between ] [ -Srold/new ] [ -V[level] ]
Note: No space is allowed between the option flag and the associated
arguments.
DESCRIPTION
grdclip will set values < low to below and/or values > high to above.
You can also specify one or more intervals where all values should be
set to IT(between), or replace individual values. Such operations are
useful when you want all of a continent or an ocean to fall into one
color or gray shade in image processing, when clipping of the range of
data values is required, or for reclassification of data values.
above, below, between, old and new can be any number or even NaN (Not a
Number). You must choose at least one of the -S options. Use -R to only
extract a subset of the ingrid file.
REQUIRED ARGUMENTS
ingrid The input 2-D binary grid file.
-Goutgrid
outgrid is the modified output grid file.
OPTIONAL ARGUMENTS
-Rxmin/xmax/ymin/ymax[+r][+uunit] (more a|)
Specify the region of interest. Using the -R option will select
a subsection of ingrid grid. If this subsection exceeds the
boundaries of the grid, only the common region will be
extracted.
-Sahigh/above
Set all data[i] > high to above.
-Sblow/below
Set all data[i] < low to below.
-Silow/high/between
Set all data[i] >= low and <= high to between. Repeat the
option for as many intervals as are needed.
-Srold/new
Set all data[i] == old to new. This is mostly useful when your
data are known to be integer values. Repeat the option for as
many replacements as are needed.
-V[level] (more a|)
Select verbosity level [c].
-^ or just -
Print a short message about the syntax of the command, then
exits (NOTE: on Windows just use -).
-+ or just +
Print an extensive usage (help) message, including the explana-
tion of any module-specific option (but not the GMT common
options), then exits.
-? or no arguments
Print a complete usage (help) message, including the explanation
of all options, then exits.
GRID FILE FORMATS
By default GMT writes out grid as single precision floats in a
COARDS-complaint netCDF file format. However, GMT is able to produce
grid files in many other commonly used grid file formats and also
facilitates so called apackinga of grids, writing out floating point
data as 1- or 2-byte integers. (more a|)
EXAMPLES
To set all values > 70 to NaN and all values < 0 to 0 in file data.nc:
gmt grdclip data.nc -Gnew_data.nc -Sa70/NaN -Sb0/0 -V
To reclassify all values in the 25-30 range to 99, those in 35-39 to
55, exchange 17 for 11 and all values < 10 to 0 in file classes.nc, try
gmt grdclip classes.nc -Gnew_classes.nc -Si25/30/99 -Si35/39/55 -Sr17/11 -Sb10/0 -V
SEE ALSO
gmt(1), grdlandmask(1), grdmask(1), grdmath(1), grd2xyz(1), xyz2grd(1)
COPYRIGHT
2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.2 Jun 24, 2017 grdclip(1)
gmt5 5.4.2 - Generated Wed Jun 28 18:14:47 CDT 2017