1 - Introduction

Abstract

Interactive Data Language (IDL) is a software system that is produced and sold by Research Systems Inc. of Boulder, Colorado consisting: (1) an interactive programming environment, and (2) a programming language. It is used in a wide range of science and engineering disciplines for processing and analyzing numerical and image data. It draws features from many other programming languages, including FORTRAN, C, BASIC, and APL, but these are different from IDL, for instance, it is possible to type a command and see the results in IDL immediately unlike other languages. Reasons to use IDL: (1) it can take a quick look at a data set without writing an entire program for that purpose. (2) “Programmer's loop” of write-compile-execute-debug, can be done very quickly without the use of special software known as a “debugger.” (3) It contains a large number of built-in functions for statistics, graphics, linear algebra, etc. (4) It is easy to write self-contained programs in IDL with interactive interfaces: menus, buttons, windows, dialog boxes, and graphics. The chapter describes the usage of interpreter, which translates IDL statements into instructions that the computer can understand and execute. In addition to command-line interpreter IDL has device drivers which are software packages that allow it to display graphics on different types of graphic devices. Recent versions of IDL include a complete software development environment that can be used to run and edit IDL programs and to display graphics.