gnuplot documentation

68 gnuplot 4.3 60 PLOT
default: assume file endianess is the same as compiler
swap (swab): Interchange the significance. (If things
don’t look right, try this.)
Gnuplot can support "middle" ("pdp") endian if it is compiled with that option.
60.2.2.5 Filetype For some standard binary file formats gnuplot can extract all the necessary information
from the file in question. As an example, "format=edf" will read ESRF Header File format
files. For a list of the currently supported file formats, type show datafile binary filetypes.
There is a special file type called auto for which gnuplot will check if the binary file’s extension is a
quasi-standard extension for a supported format.
Command line keywords may be used to override settings extracted from the file. The settings from the
file override any defaults. (See set datafile binary (p. 96) for details.)
60.2.2.5.1 Avs avs is one of the automatically recognized binary file types for images. AVS is an extremely
simple format, suitable mostly for streaming between applications. It consists of 2 longs (xwidth,
ywidth) followed by a stream of pixels, each with four bytes of information alpha/red/green/blue.
60.2.2.5.2 Edf edf is one of the automatically recognized binary file types for images. EDF stands
for ESRF Data Format, and it supports both edf and ehf formats (the latter means ESRF Header
Format). More information on specifications can be found at
http://www.esrf.fr/computing/expg/subgroups/general/format/Format.html
See also binary (p. 66).
60.2.2.6 Keywords The following keywords apply only when generating coordinates. That is, when
the keyword array is used.
60.2.2.6.1 Scan A great deal of confusion can arise concerning the relationship between how gnuplot
scans a binary file and the dimensions seen on the plot. To lessen the confusion, conceptually think of
gnuplot always scanning the binary file point/line/plane or fast/medium/slow. Then this keyword is
used to tell gnuplot how to map this scanning convention to the Cartesian convention shown in plots,
i.e., x/y/z. The qualifier for scan is a two or three letter code representing where point is assigned (first
letter), line is assigned (second letter), and plane is assigned (third letter). For example, scan=yx
means the fastest, point-by-point, increment should be mapped along the Cartesian y dimension and
the middle, line-by-line, increment should be mapped along the x dimension.
When the plotting mode is plot, the qualifier code can include the two letters x and y. For splot, it
can include the three letters x, y and z.
There is nothing restricting the inherent mapping from point/line/plane to apply only to Cartesian
coordinates. For this reason there are cylindrical coordinate synonyms for the qualifier codes where t
(theta), r and z are analogous to the x, y and z of Cartesian coordinates.
60.2.2.6.2 Transpose Shorthand notation for scan=yx or scan=yxz.
60.2.2.6.3 Dx, dy, dz When gnuplot generates coordinates, it uses the spacing described by these
keywords. For example dx=10 dy=20 would mean space samples along the x dimension by 10 and
space samples along the y dimension by 20. dy cannot appear if dx does not appear. Similarly, dz
cannot appear if dy does not appear. If the underlying dimensions are greater than the keywords
specified, the spacing of the highest dimension given is extended to the other dimensions. For example,
if an image is being read from a file and only dx=3.5 is given gnuplot uses a delta x and delta y of 3.5.
The following keywords also apply only when generating coordinates. However they may also be used
with matrix binary files.