• The human mind often benefits from graphical presentation of numbers.numbers image by Amer Delibasic from Fotolia.com
  
  Interactive Data Language is a computer programming language used to create images out of numbers. IDL, which was created for use in the fields of aerospace and astronomy, became much more widely used over time because in a variety of scientific fields the visualization of the underlying data is an important step in understanding its significance and moving forward to tests or applications. IDL is a product of ITT Visual Information Systems.
  
  

History

• Mars' surface mineralogy numbers are the subject of an IDL Tutorial.surface of mars. image by Petr Gnuskin from Fotolia.com
  
  IDL in its earliest forms was the product of Research Systems Inc., a company founded by David Stern. In 1981 RSI released a version designed for VAX/VMS, the architecture used by Digital Equipment Corporation at the time.
  
  Although IDL's earliest use was in astronomy and the space sciences, it soon proved adaptable to such fields as medicine and nuclear physics. According to Liam E. Gumley of the University of Wisconsin, Madison, the language is used in "monitoring and controlling the plasma field of a nuclear fusion tokamak."
  
  ITT Industries bought RSI in 2004 and rebranded it as ITT VIS in 2006.
  
  

Starting In

• You can simply type
  
  idl
  
  to run a traditional command-line interface, or you can type
  
  idlde
  
  for IDL Development Environment, to get a more flexible display with built-in editing tools.
  
  In either case, the prompt looks like this: IDL>
  
  Whereupon interaction can go in any of hundreds of directions. In just five commands, within either IDL or IDLDE, one can produce the plot of a damped sine wave. That would work thus (pressing RETURN) after typing each command):
  
  IDL> x=findgen(100)
  
  IDL> x=x/50
  
  IDL> y=sin(3*!Pi*x)/EXP(x)
  
  IDL> PLOT, x, y
  
  IDL> wdelete.
  
  As Chris Rennie, of the School of Physics at the University of Sydney, Australia has explained, the first of those commands generates an array of 100 floats assigned to the variable x.
  
  The second command scales that array.
  
  The third introduces the functions sin() and exp(). As Rennie says, IDL is indiferent to case, so that exp is identical to EXP or to ExP.
  
  The fourth plots the array y as a function of x.
  
  Finally, the fifth line dismisses the graphics window.
  
  

IDL 8.0

• The latest generation of IDL is IDL 8.0, which has an updatd "workbenchg programming environment ... so it's easier to create small programs and large-scale applications" according to the ITT website. The workbench includes a simplified interface, new features for the insertion of code templates, an improved toolbar and a help system.
  
  

Caution

• The initials IDL can also mean "Interface Description Language" (also known as "Interface Definiton Language"). That IDL is a specification language used to serve as a bridge between software components that do not share a language.