(From the OpenDX web site) OpenDX gives you new control over your data...and new insights into their meaning. Yet OpenDX is easy to use because it lets you visualize data in ways you've never dreamed of--without getting bogged down in the technology. As its name implies, OpenDX is Open Source. The license allows you to freely create, distribute, and develop visualization solutions as you see fit. OpenDX is a uniquely powerful, full-featured software package for the visualization of scientific, engineering and analytical data: Its open system design is built on a standard interface environment. And its sophisticated data model provides users with great flexibility in creating visualizations. With OpenDX, you can create the visualizations you want to create. OpenDX has been designed to be the place where the art of science and the science of visualization come together. It's the place where they're combined into one powerful, flexible framework that lets you "Simply Visualize." OpenDX is the open source software version of IBM's Visualization Data Explorer Product. The last release of Data Explorer from IBM was 3.1.4B; the open source version is based on this version with the license manager removed and set up to reflect an open source project. The developers have put in a lot of work to provide a clean set of code that can be compiled on a multitude of platforms.
OpenDX is freely downloadable open-source application from http://www.opendx.org/.
Free for most platforms, commercial versions available for Mac OSX and Windows ($25).
Open source versions exist for Irix, HP-UX, Linux, Solaris, and Windows (using Cygwin or other X-windows emulator). Commercial versions exist for Mac OSX and Windows (no need for X-windows).
OpenDX uses a native (.dx) data file format, but this format is clearly described in the support documents, and there are add-on conversion apps that can convert some image a data file formats (DEM, DLG, ERDAS/IMG, DXF, for example) to the .dx format. OpenDX also includes a 'general array importer' that allows you to specify the general format of your data for importing.
Integrating with other Tools
Since the OpenDX source is freely available, it is possible to integrate it with just about any other application you desire that may support such integration. There are Add-ons to OpenDX supporting integration with Python and Tcl/Tk, and we have also had success using JNI to create a Java-based interface to certain OpenDX modules, for example.
OpenDX is designed as a scientific data analysis and visualization tool. It can handle extremely large datasets with relative ease, and comes with a set of analysis and visualization modules that compare well with high-end expensive apps such as AVS, Matlab, and Mathematica. Still, it is a general tool that is not designed to excel at any one specific discipline, so for advanced analysis you may find it is missing certain discipline-specific features. Also, since it is open source, don't expect its feature set to be extended anytime soon. It has remained relatively static for a few years (version 4.3.2 is the latest as of this writing).
OpenDX outputs to its own .dx format, but you may also export vrml, bitmaps, and movies of your resulting visualizations. If you are a programmer, you may customize the code to output in any format you desire and are familiar with. Remember, since it was originally developed for a unix environment, to work with the source code you will need to be comfortable with a variety of support tools.
OpenDX is designed as a "Visual Programming Language", wherein you click and drag modules (represented by box-like icons) into a window for the various functions you desire for your program. You then click and drag connections between the modules and modify various parameters in popup dialog boxes to refine your program. OpenDX is not for the novice. In fact advanced programmers can be somewhat intimidated by the complexity and sophistication of the interface. There are a small number of books written to help learn OpenDX, as well as a wide range of sample applications. Still, it requires extreme persistence and determination to consider yourself a master of the application.