How to Plot Data Using IDL

Barbara Anne am Ende
October 1, 1998


The goals of these web pages are to teach how to: These examples will not replace the on-line help or the manuals, but are intended as guides for the type of work you might have.  Another useful manual is IDL Programming Techniques by David W. Fanning.

What is IDL?

IDL stands for Interactive Data Language, and is available through Research Systems, Inc.   Research Systems describes IDL as a "complete computing environment for the interactive analysis and visualization of data.  IDL integrates a powerful, array-oriented language with numerous mathematical analysis and graphical display techniques."

Handy syntax to know before you get started:

"How To" Links
Be sure to glance at the re-write examples.  There are many "how to" examples show there as well.

How to Customize Graphs in IDL
How to Overlay a Contour Graph over a 2D Plot
How to Save to a Postscript File
How to Make Axis Titles Larger than Axis Values
How to Manipulate Arrays and Read Columns of Data from Files
How to Position Graphs on a Postcript Page
How to Print
How to Start Up in IDL
How to Compile IDL code
How to Compile Callable IDL from Fortran
How to Use Batch Files
How to Understand the Difference Between System Variable and Keywords

Which NIST machines can you use?
You can use IDL on any of the machines (visit the SAVG web pages).  However, note that all the help in this section is based on SGI machines.  You can also use Sun machines, but the flags in the Makefile will be different (to find them, look into the calltest example found in /itl/apps/idl-5.1/idl_5.1/external.  You'll also want to look in the chapter "Using Callable IDL."  It is located in the External Development Guide (aka Advanced Development Guide, v. 5.0).

Gaithersburg machines which are best to use:

Boulder machines which are best to use:

Issues with Arno:
Arno is a new machine and the rules are not in place as of this writing (10-01-98).  However, it appears that all programs used on arno should be batch files.  This means you cannot work interactively on arno.  Therefore, you should probably use one of the other public machines.  If you have extensive computations, send them as a batch to arno.  Have the output saved as a data file.  Plot the data using IDL on one of the public machines such as lime.