GNUPlot Manual

156 gnuplot 4.0 38 SPLOT
In previous versions, gnuplot dynamically detected binary data files. It is now necessary to specify the
keyword binary directly after the filename.
Single precision floats are stored in a binary file as follows:
...
...
...
: : : : ... :
which are converted into triplets:
: : :
: : :
These triplets are then converted into gnuplot iso-curves and then gnuplot proceeds in the usual
manner to do the rest of the plotting.
A collection of matrix and vector manipulation routines (in C) is provided in binary.c. The routine to
write binary data is
int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)
An example of using these routines is provided in the file bf test.c, which generates binary files for the
demo file demo/binary.dem.
The index keyword is not supported, since the file format allows only one surface per file. The every
and using filters are supported. using operates as if the data were read in the above triplet form. See
also
Binary File Splot Demo.
38.1.2 Example datafile
A simple example of plotting a 3-d data file is
splot ’datafile.dat’
where the file "datafile.dat" might contain:
# The valley of the Gnu.
0 0 10
0 1 10
0 2 10
1 0 10
1 1 5
1 2 10
2 0 10
2 1 1
2 2 10
3 0 10
3 1 0
3 2 10