grdreformat

       grdreformat  -  Converting  between different grdfile for­
       mats.

SYNOPSIS

       grdreformat ingrdfile[=id[/scale/offset[/nanvalue]]]  out­
       grdfile[=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 min­
              utes  [and  seconds],  use  the  dd:mm[:ss] format.
              Append r if lower left and upper right map  coordi­
              nates are given instead of wesn.

       -V     Selects  verbose  mode,  which  will  send progress
       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, sub­
       tract 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(l), grdmath(l)