NAME

       grdclip - Clip the range of grids

SYNOPSIS

       grdclip  ingrid  outgrid [ region ] [ ahigh/above ] [ blow/below ] [ ilow/high/between ] [
       rold/new ] [ [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

       -R[unit]xmin/xmax/ymin/ymax[r] (more ...)
              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 ...)
              Select verbosity level [c].

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows
              use just -).

       -+ or just +
              Print  an  extensive  usage  (help)  message,  including  the  explanation  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  options,  then
              exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

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 "packing" of grids, writing out floating point
       data as 1- or 2-byte integers. To specify the precision, scale and offset, the user should
       add  the  suffix =id[/scale/offset[/nan]], where id is a two-letter identifier of the grid
       type and precision, and scale and offset are  optional  scale  factor  and  offset  to  be
       applied  to  all  grid values, and nan is the value used to indicate missing data. In case
       the two characters id is not provided, as in  =/scale  than  a  id=nf  is  assumed.   When
       reading  grids,  the format is generally automatically recognized. If not, the same suffix
       can be added to input grid file names. See grdconvert and Section grid-file-format of  the
       GMT Technical Reference and Cookbook for more information.

       When  reading  a  netCDF file that contains multiple grids, GMT will read, by default, the
       first 2-dimensional grid that can find in that file. To  coax  GMT  into  reading  another
       multi-dimensional  variable  in  the  grid  file,  append ?varname to the file name, where
       varname is the name of the variable. Note that you may need to escape the special  meaning
       of  ?  in  your  shell  program  by  putting a backslash in front of it, or by placing the
       filename and suffix between quotes or double quotes. The ?varname suffix can also be  used
       for  output  grids  to  specify  a  variable  name  different  from  the default: "z". See
       grdconvert and  Sections  modifiers-for-CF  and  grid-file-format  of  the  GMT  Technical
       Reference  and  Cookbook  for more information, particularly on how to read splices of 3-,
       4-, or 5-dimensional grids.

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, grdlandmask, grdmask, grdmath, grd2xyz, xyz2grd

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe