3.15.2 binary

BINARY DATA FILES:

Some earlier versions of ‘gnuplot‘ automatically detected binary data files. It is now necessary to provide the keyword binary after the filename. Adequate details of the file format must be given on the command line or extracted from the file itself for a supported binary filetype. In particular, there are two structures for binary files, binary matrix format and binary general format.

The matrix format contains a two dimensional array of 32 bit IEEE float values with an additional column and row of coordinate values. As with ASCII matrix, in the using list, enumeration of the coordinate row constitutes column 1, enumeration of the coordinate column constitutes column 2, and the array of values constitutes column 3.

The general format contains an arbitrary number of columns for which information must be specified at the command line. For example, array, record, ‘format‘ and using can indicate the size, format and dimension of data. There are a variety of useful commands for skipping file headers and changing endianess. There are a set of commands for positioning and translating data since often coordinates are not part of the file when uniform sampling is inherent in the data. Different from matrix binary or ASCII, general binary does not treat the generated columns as 1, 2 or 3 in the using list. Rather, column 1 begins with column 1 of the file, or as specified in the ‘format‘ list.

There are global default settings for the various binary options which may be set using the same syntax as the options when used as part of the ‘(s)plot <filename> binary ...‘ command. This syntax is ‘set datafile binary ...‘. The general rule is that common command-line specified parameters override file-extracted parameters which override default parameters.

matrix is the default binary format when no keywords specific to general are given, i.e., array, record, ‘format‘, filetype.

General binary data can be entered at the command line via the special file name ’-’. However, this is intended for use through a pipe where programs can exchange binary data, not for keyboards. There is no "end of record" character for binary data. Gnuplot continues reading from a pipe until it has read the number of points declared in the array qualifier. See matrix or general for more details.

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. Binary File Splot Demo.

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