Asymptote is a powerful descriptive 2D and 3D vector graphics language for technical drawing, inspired by MetaPost but with an improved C++-like syntax. It provides for figures the same high-quality level of typesetting that LaTeX does for scientific text. Asymptote is a programming language as opposed to just a graphics program. It can exploit the best features of script (command-driven) and graphical user interface (GUI) methods. High-level graphics commands are implemented in the language itself, allowing them to be easily tailored to specific applications.
R is a language and environment for statistical computing and graphics. It is similar to S, which was developed at Bell Laboratories by John Chambers et al. It provides a wide variety of statistical and graphical techniques (linear and nonlinear modelling, statistical tests, time series analysis, classification, clustering, etc.). R is designed as a true computer language with control-flow constructions for iteration and alternation, and it allows users to add additional functionality by defining new functions. For computationally intensive tasks, Fortran and C code can be linked and called at run time.
VisIt is an interactive parallel visualization and graphical analysis tool for viewing scientific data. Users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images for presentations. VisIt contains a rich set of visualization features so that you can view your data in a variety of ways. It can be used to visualize scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured and unstructured meshes. It was designed to interactively handle very large data set sizes in the terascale range, and works well down to small data sets in the kilobyte range.
Engauge Digitizer is digitizing software that converts an image showing a graph or map into numbers. The image file can come from a scanner, digital camera, or screenshot. The numbers can be read on the screen, and written or copied to a spreadsheet. Highlights for beginners include an intuitive interface and extensive context-sensitive documentation. Highlights for experts include compensation for image distortion, cartesian and polar coordinates, linear and logarithmic coordinates, automatic scanning, graphical previews, and browser help.
Evolvotron is an interactive "generative art" application to evolve images/textures/patterns through an iterative process of random mutation and user-selection driven evolution. If you like lava lamps, and never got tired of the Mandelbrot set, this could be the software for you. It's implemented using Qt, and is multithreaded.
Gnofract 4D is a Gnome-based program to draw fractals. What sets it apart from other fractal programs (and makes it "4D") is the way that it treats the Mandelbrot and Julia sets as different views of the same four-dimensional fractal object. It contains a Fractint-compatible formula compiler, allowing it to draw an unlimited number of fractal types, using numerous coloring options.
MayaVi is a free, cross platform, easy-to-use scientific data visualizer. It provides a powerful GUI to ease the visualization process. It is written in Python and uses the Visualization Toolkit (VTK) for the graphics. MayaVi can be scripted from other Python programs and also from the interactive Python interpreter. MayaVi includes the VTK Pipeline browser. The VTK Pipeline browser is a Python module (vtkPipeline) that enables one to view and configure the objects in the VTK pipeline graphically with a Tkinter-based GUI. The browser should work for any Python script that uses VTK. MayaVi also provides classes to pickle a VTK object and a simple class documentation browser.