Simple OS X "droplet" for quick data visualization. Drag-and-drop one or more text files containing series data and a simple scatter plot is generated containing each series with different symbols, legend, etc. GUI-less alternative to gnome PlotDrop.
MayaVi is a free, cross platform, easy to use scientific data visualizer. It provides a GUI to ease the visualization process, is written in Python and uses the Visualization Toolkit (VTK) for the graphics.
...It implements many graph layout algorithms (such as force-directed methods), graph generators (such as scale-free networks) and graph modifiers. Most functions can be accessed through its GUI.
A GUI built using Python 2.3+, wxPython and PyOpenGL for the mathematical modeling and visualization of landscape and streamflow systems. This visualization tool uses the Channel-Hillslope Integrated Landscape Development (CHILD) model as its backend.
Real-time data visualization. Graphically view your data as it's being generated. Peakster is a very intuitive GUI written entirely in Python, which monitors data at regular intervals and uses gnuplot to render 2D, 3D and superimposed plots.
Soto is a graphical message debugger for simpleIPC. In addition to displaying the message traffic between processes, it can log and play back this traffic. Soto also provides the ability to design GUI "panes" that are populated with data from messages.