- A pipe-based interface to the gnuplot plotting program.
This is the main module of the Gnuplot package.
Written by "Michael Haggerty", mailto:firstname.lastname@example.org. Inspired
by and partly derived from an earlier version by "Konrad Hinsen",
mailto:email@example.com. If you find a problem or have a suggestion,
please "let me know", mailto:firstname.lastname@example.org. Other feedback
would also be appreciated.
The Gnuplot.py home page is at
For information about how to use this module:
Check the README file.
Look at the example code in demo.py and try running it by typing
python demo.py or
For more details see the extensive documentation strings
throughout the python source files, especially this file,
_Gnuplot.py, PlotItems.py, and gp_unix.py.
The docstrings have also been turned into html which can be read
"here", http://gnuplot-py.sourceforge.net/doc. However, the
formatting is not perfect; when in doubt, double-check the
You should import this file with
import Gnuplot, not with
Gnuplot import *, because the module and the main class have the same
To obtain the gnuplot plotting program itself, see "the gnuplot FAQ",
ftp://ftp.gnuplot.vt.edu/pub/gnuplot/faq/index.html. Obviously you
need to have gnuplot installed if you want to use Gnuplot.py.
The old command-based interface to gnuplot (previously supported as
oldplot.py) has been removed from the package.
Allows the creation of two or three dimensional plots from
A gnuplot session is an instance of class
sessions can be open at once. For example:
g1 = Gnuplot.Gnuplot()
g2 = Gnuplot.Gnuplot()
Note that due to limitations on those platforms, opening multiple
simultaneous sessions on Windows or Macintosh may not work
The implicitly-generated gnuplot commands can be stored to a file
instead of executed immediately:
g = Gnuplot.Gnuplot('commands.txt')
The 'commands.txt' file can then be run later with gnuplot's
'load' command. Beware, however: the plot commands may depend on
the existence of temporary files, which will probably be deleted
before you use the command file.
Can pass arbitrary commands to the gnuplot command interpreter:
g('set pointsize 2')
(If this is all you want to do, you might consider using the
lightweight GnuplotProcess class defined in gp.py.)
A Gnuplot object knows how to plot objects of type
Any PlotItem can have optional
Builtin PlotItem types:
Data(array1) -- data from a Python list or NumPy array
(permits additional option
filename)' -- data from an existing data file (permits
exp(4.0 * sin(x)))' -- functions (passed as a string,
evaluated by gnuplot)
GridData(m, x, y) -- data tabulated on a grid of (x,y) values
(usually to be plotted in 3-D)
See the documentation strings for those classes for more details.
PlotItems are implemented as objects that can be assigned to
variables and plotted repeatedly. Most of their plot options can
also be changed with the new
set_option() member functions then
they can be replotted with their new options.
Communication of commands to gnuplot is via a one-way pipe.
Communication of data from python to gnuplot is via inline data
(through the command pipe) or via temporary files. Temp files are
deleted automatically when their associated
PlotItem is deleted.
The PlotItems in use by a Gnuplot object at any given time are
stored in an internal list so that they won't be deleted
replot method to add datasets to an existing plot.
Can make persistent gnuplot windows by using the constructor option
persist=1. Such windows stay around even after the gnuplot
program is exited. Note that only newer version of gnuplot support
Can plot either directly to a postscript printer or to a
postscript file via the
Grid data for the splot command can be sent to gnuplot in binary
format, saving time and disk space.
Should work under Unix, Macintosh, and Windows.
Relies on the Numeric Python extension. This can be obtained from
"SourceForge", http://sourceforge.net/projects/numpy/. If you're
interested in gnuplot, you would probably also want NumPy anyway.
Only a small fraction of gnuplot functionality is implemented as
explicit method functions. However, you can give arbitrary
commands to gnuplot manually:
g = Gnuplot.Gnuplot()
g('set data style linespoints')
g('set pointsize 5')
There is no provision for missing data points in array data (which
gnuplot allows via the
set missing command).
No attempt is made to check for errors reported by gnuplot. On
unix any gnuplot error messages simply appear on stderr. (I don't
know what happens under Windows.)
All of these classes perform their resource deallocation when
__del__ is called. Normally this works fine, but there are
well-known cases when Python's automatic resource deallocation
fails, which can leave temporary files around.