GRDREFORMAT(l)															    GRDREFORMAT(l)

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.)  For format =id > 0 the size of the GMT grdheader block is hsize = 896 bytes,  and	the  total
	      size  of	the  file  is  hsize  + nx * ny * item_size, where item_size is the size in bytes of each element (1, 2, 4). Bit grids are
	      stored using 4-byte integers, each holding 32 bits, so for these files the size equation is modified by using ceil (nx  /  32)  *  4
	      instead of nx. For header and grid details, see Appendix B.

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(1gmt), grdmath(1gmt)

								    1 Jan 2004							    GRDREFORMAT(l)