NAME

       grd2rgb - Write r/g/b grid files from a grid file, a raw RGB file, or SUN rasterfile

SYNOPSIS

       grd2rgb  infile  template  [  cpt  ]  [ xinc[m|s][/yinc[m|s]] ] [ layer ] region [level] [
       width/height[/n_bytes] ] [ -r ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       grd2rgb reads one of three types of input files: (1) A Sun 8-, 24-, or 32-bit raster file;
       we the write out the red, green, and blue components (0-255 range) to separate grid files.
       Since the raster file header is limited you may use the  -R,  -I,  -r  options  to  set  a
       complete  header record [Default is simply based on the number of rows and columns]. (2) A
       binary 2-D grid file; we then convert the z-values to red, green, blue  via  the  provided
       CPT  file.  Optionally,  only  write out one of the r, g, b, layers. (3) A RGB or RGBA raw
       raster file. Since raw rasterfiles have no header, you have to give the  image  dimensions
       via the -W option.

REQUIRED ARGUMENTS

       infile The  (1)  Sun  raster  file, (2) 2-D binary grid file, or (3) raw raster file to be
              converted.

       -Gtemplate
              Provide an output name template for the three output grids. The template should  be
              a  regular grid file name except it must contain the string %c which on output will
              be replaced by r, g, or b.

OPTIONAL ARGUMENTS

       -Ccpt  name of the color palette table (for 2-D binary input grid only).

       -Ixinc[unit][=|+][/yinc[unit][=|+]]
              x_inc [and optionally y_inc] is the  grid  spacing.  Optionally,  append  a  suffix
              modifier. Geographical (degrees) coordinates: Append m to indicate arc minutes or s
              to indicate arc seconds. If one of the units e,  f,  k,  M,  n  or  u  is  appended
              instead,  the  increment  is assumed to be given in meter, foot, km, Mile, nautical
              mile or US survey foot, respectively, and  will  be  converted  to  the  equivalent
              degrees  longitude  at the middle latitude of the region (the conversion depends on
              PROJ_ELLIPSOID). If /y_inc is given but set to 0 it will be reset equal  to  x_inc;
              otherwise  it  will  be  converted  to  degrees  latitude. All coordinates: If = is
              appended then the corresponding max x (east) or y (north) may be slightly  adjusted
              to  fit  exactly  the  given  increment  [by  default the increment may be adjusted
              slightly to fit the given domain]. Finally, instead of giving an increment you  may
              specify  the  number  of  nodes  desired  by  appending  +  to the supplied integer
              argument; the increment is then recalculated from  the  number  of  nodes  and  the
              domain.  The  resulting  increment  value  depends  on  whether you have selected a
              gridline-registered or pixel-registered grid;  see  App-file-formats  for  details.
              Note:  if -Rgrdfile is used then the grid spacing has already been initialized; use
              -I to override the values.

       -Llayer
              Output only the specified layer (r, g, or b). [Default outputs all 3 layers].

       -R[unit]xmin/xmax/ymin/ymax[r] (more ...)
              Specify the region of interest.

       -V[level] (more ...)
              Select verbosity level [c].

       -Wwidth/height[/n_bytes]
              Sets the size of the raw  raster  file.  By  default  an  RGB  file  (which  has  3
              bytes/pixel)  is  assumed. For RGBA files use n_bytes = 4.  Use -W for guessing the
              image size of a RGB raw file, and -W=/=/4 if the raw image is  of  the  RGBA  type.
              Notice  that  this might be a bit slow because the guessing algorithm makes uses of
              FFTs.

       -r (more ...)
              Set pixel node registration [gridline].

       -^ 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.

EXAMPLES

       To  use  the  color  palette topo.cpt to create r, g, b component grids from hawaii_grv.nc
       file, use

              gmt grd2rgb hawaii_grv.nc -Ctopo.cpt -Ghawaii_grv_%c.nc

       To output the red component from the Sun raster radiation.ras file, use

              gmt grd2rgb radiation.ras -Lr -Gcomp_%c.nc

SEE ALSO

       gmt, gmt.conf, grdedit, grdimage, grdmath , grdview

COPYRIGHT

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