Graphical Representations of Data

Image Processing and Analysis

• The PIL Toolkit provides a very powerful set of tools for manipulating images. Its documentation is available at Pythonware.com

Plotting Tools

• Chaco is a device-independent 2D plotting package based on the DisplayPDF API being developed for Python by Enthought with support from the Space Science Telescope Institute.
• Konrad Hinsen has some plotting support in his ScientificPython package, for example TkPlotCanvas.
• Michael Haggerty has a Gnuplot module which interfaces with the GNUPLOT package, based.
• plot_wrap
  A module by Mike Miller which wraps the functions in the GNU plotutils package.
• BLT
  BLT is an extension to the tk widgets, which can produce X/Y plots and bar charts. The BLT package can be used through the Pmw package, a framework for the creation of megawidgets building on top of Tkinter.
• DISLIN
  DISLIN is a high-level and easy to use graphics library for displaying data as curves, bar graphs, pie charts, 3D-color plots, surfaces, contours and maps. The software is available for several C, Fortran 77 and Fortran 90 compilers. For some operation systems, the programming languages Python and Perl are also supported by DISLIN. DISLIN is free for the operating systems Linux and FreeBSD and for the MS-DOS and Windows 95/NT compilers GCC, G77 and ELF90. Other DISLIN versions are available at low prices and can be tested free of charge.
• gdmodule
  GD is a graphics library for the creation of GIF pictures, written by Thomas Boutell. The gdmodule is an Python extension for this library. It can do line, arcs, fills, fonts and can also manipulate other GIF pictures. Included in the gdmodule is a graphing module, which can produce line plots from data.
• Gist
  Extension to the gist graphics library, which is part of another numeric environment named yorick. It can produce line, contour, surface plots on quadrilateral meshes. On top of the low-level interface the people from LLNL have build an object-oriented interface which can also do isosurface and 3D slicing plots together with light and script based animation. The interface is well documented. The package is now part of the LLNL Python distribution. Gist originally ran only under Unix-like operating systems. The latest source and a Windows installer are available from the University of Tokyo.
• Gnuplot
  Michael Haggerty has written a module to communicate with Gnuplot from within Python.
• pgplot
  Extension to the pgplot graphics library, a portable, device independent graphics package for making simple scientific graphs. The library is intended for making graphical images of publication quality with minimum effort on the part of the user. All functions are directly callable from Python, through the use of SWIG for wrapper code generation. Pgplot has drivers for many different graphics formats and devices, although there are problems with the MS-Windows driver.
• Py-OpenDX
  OpenDX is the open-source version of the IBM Data Explorer (DX). DX is a visualization system providing a full set of tools for manipulating, rendering and animating data, especially 3D data from simulations or acquired from observations. It provides a GUI, a scripting interface and the API C libraries. Py-OpenDX is a Python binding for the OpenDX API. Currently only the DXLink library is wrapped. That wrapper allows one to start up a DX executive and communicate with it via the DXL API.
• VTK
  VTK is an OO-framework for visualisation, written in C++ with bindings to TCL, Python and Java. It's not really a plotting package, but a visualisation system, where one needs to program to get a picture. It's very huge and resource demanding and best used on hardware with good graphics performance. It uses mainly OpenGL for rendering, so it can not produce vector graphics or high quality postscript output. Besides of that VTK is very powerful and can produce really great views of your data.
• RPy -- a Python interface to the R programming language. R is a large, robust package for doing math and statistics; it includes many, many graphing options.
  
• Matplotlib is a pure Python plotting library designed to support publication quality plotting with a syntax familiar to Matlab users. All of the plotting commands can be accessed either via a functional interface familiar to Matlab users or an object oriented interface familiar to Python users, and several high resolution output formats are supported.
• PyX is a library for creating figures in Encapsulated PostScript.
• Biggles is another plotting library that supports multiple output formats, as is Piddle.
• Pychart is a library for creating EPS, PDF, PNG, and SVG charts. It supports line plots, bar plots, range-fill plots, and pie charts.

Also Of Note:

• Janko Hauser maintains a list similar to this one of "Plotting with Python" tools, from which many of the above was stolen (with permission).

• There is an interface to the OpenGL library, called PyOpenGL, which can be used to write sophisticated visualization tools from scratch.

• The FXPy bindings to the FOX GUI library support OpenGL, so might be a good starting point for new applications.