Next: , Previous: data-file_, Up: data-file_


2.21.1.1 binary

`splot` can read binary files written with a specific format (and on a system with a compatible binary file representation.)

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:

           <N+1>  <y0>   <y1>   <y2>  ...  <yN>
            <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
            <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
             :      :      :      :   ...    :
     

which are converted into triplets:

           <x0> <y0> <z0,0>
           <x0> <y1> <z0,1>
           <x0> <y2> <z0,2>
            :    :     :
           <x0> <yN> <z0,N>
     
           <x1> <y0> <z1,0>
           <x1> <y1> <z1,1>
            :    :     :
     

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.