Scientific instruments are good at collecting data, but some people need to see images, instead of numeric tables, in order to easily interpret data.
Research Systems’ IDL 6.0 is the best of its kind at providing visual images that represent statistics — it can turn radar into weather maps, MRI signals into pictures of a skull, and space X-ray signals into maps of the universe.
Other programs, such as The MathWorks’
; December 2002) and Wolfram Research’s
; January 2004), can map 2-D and 3-D data arrays into dazzling color plots. But IDL’s tool set gives you more types of charts, as well as better chart-labeling components that make it easier to generate finished presentations.
Version 6.0’s new iTools feature makes complex plotting easier for beginners, while the new, free IDL Virtual Machine lets nonusers customize display features.
Speaking the Language
IDL stands for Interactive Data Language, a name that doesn’t really explain much. The application uses a C-like programming language that offers hundreds of special functions for different kinds of data display; you might call IDL “Adobe Photoshop for scientists.” For example, if you have seismic data to chart, you can elect to display it in as many as 20 global projections, using the program’s variety of built-in color tables.
Version 6.0 of IDL introduces “intelligent tools” called iTools (not to be confused with Apple’s defunct iTools). This object-oriented programming system has an assortment of premade tools that help you produce graphic representations of 2-D and 3-D plots (line, scatter, polar, and histogram), surface representations, contour maps, image displays, and volume visualizations. iTools give you many types of displays with a single command.
iTools commands also can be modified and combined into custom libraries.
With version 6.0, Research Systems is introducing IDL Virtual Machine, a freely distributable module that runs compiled IDL code. IDL VM is not yet bug free. Users who upgraded from version 5.5 have encountered problems with iTools code in the virtual machine. Those problems, and glitches in IDL object graphics, were mostly caused by the previous version’s non-Unix file conventions. Very few problems, though, have been reported with the virtual machine running from the native 6.0 code.
IDL and Panther
The Mac version of IDL is actually Unix. To run it, you need OS X 10.3, because Panther’s version of X11 Windows eliminates some of the problems with version 5.5. This also applies to the virtual machine, so you can’t distribute IDL code to your Mac pals unless they’ve upgraded to Panther, too.
Macworld’s Buying Advice
IDL offers data-visualization tricks not available in any other math application, and version 6.0 is significantly easier for newcomers to use.