NAME

      grdreformat - Converting between different grdfile formats.

SYNOPSIS

      grdreformat ingrdfile[=id[/scale/offset[/nanvalue]]]
      outgrdfile[=id[/scale/offset[/nanvalue]]] [ -Rwest/east/south/north[r]
      ] [ -V ]

DESCRIPTION

      grdreformat reads a grdfile in one format and writes it out using
      another format.  As an option the user may select a subset of the data
      to be written and to specify scaling, translation, and nan-value.

      ingrdfile
           The grdfile to be read.  Append format =id number if not a
           standard GMT netcdf-based grdfile.  If id is set, you may
           optionally append scale and offset to scale the data and then add
           an offset.  If scale and offset are supplied you may also append
           a value that represent 'not-a-number' (for floating-point grids
           this is unneccesary since the IEEE NaN is used; however short
           integers need a value which means no data available.)

      outgrdfile
           The grdfile to be written.  Append format =id number if not a
           standard GMT netcdf-based grdfile.  If id is set, you may
           optionally append scale and offset to scale the data and then add
           an offset.  If scale and offset are supplied you may also append
           a value that represent 'not-a-number' (for floating-point grids
           this is unneccesary since the IEEE NaN is used; however short
           integers need a value which means no data available.)

OPTIONS

      -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.

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

EXAMPLES

      To create a 4-byte raw floating point grid from the netcdf file
      data.grd, try

      grdreformat data.grd ras_data.b4=1 -V

      To make a 2-byte short integer file, scale it by 10, subtract 32000,
      setting NaNs to -9999, do

      grdreformat values.grd shorts.i2=2/10/-32000/-9999 -V

      To create a Sun standard 8-bit rasterfile for a subset of the data
      file image.grd, assuming the range in image.grd is 0-1 and we need 0-
      255, try

      grdreformat image.grd -R-60/-40/-40/-30 image.ras8=3/255/0 -V

SEE ALSO

      gmt, grdmath