IDL

What is IDL?

IDL is a scientific computing environment that combines mathematics, advanced data visualization, scientific graphics, and a graphical user interface toolkit to analyze and visualize scientific data.

Designed for use by scientists and scientific application developers, IDL's array-oriented, fourth-generation programming language allows you to prototype and develop complete applications.

Programming

Complete, structured language
Immediate execution of interactive statements
Extensible: add your own FORTRAN or C code with child processes or dynamic linking
Data structures: scalar, vector, array, and aggregate structures
Data types:
- byte
- short and long integer
- single and double-precision floating-point
- complex
- string
Operators, procedures, and functions operate directly and efficiently on scalars, vectors and arrays without loops
User-definable functions and procedures
Create arrays as large as virtual memory allows
Complete set of array handling functions
Conventional infix notation and syntax
Window-based, on-line help

Math Functions

Built-in matrix operators
Matrix inversion
SVD and LU Decomposition
Complete set of transcendental functions
Complex arithmetic
Differentiation and integration
Bessel functions
2D surface fitting
Interpolation using Kriging
Numerical Recipes mathematics routines

2D Plotting

Line plots, scatter plots, histograms, bar graphs, polar plots, error bars
Automatic plots with numerous customizable defaults
Log, semi-log, and linear scaling
Overplot multiple data sets
Linestyle, color, and marker type control
Ganged plots
Vector flow diagrams
Interactive plotting tool

Surface Plotting

Contour plots, filled contours, automatic closing of contour boundaries
Mesh surface plots with hidden line removal
Shaded surface representations of solids and gridded elevations
Regular and irregular gridding using Delaunay triangulation
Surface interpolation of irregularly gridded data points
"4D" data display of gridded elevations with overlaid image or user-specified shading
User-definable, 3D transformations

3D Graphics

Z-buffered graphics
Volume contouring (iso-surfacing)
Voxel rendering

Mapping Functions

Twelve geographic mapping transformations with inverses
Warp image data onto arbitrary projections

Image Processing

Interactive contrast enhancement
Histogram equalization
Combine images with other two- and three-dimensional graphics
Hardware and/or software zoom and pan
Image annotation
Display images on pseudo-color, true-color and bi-level devices
Generalized image arithmetic with pixels of any data type
Histogram processing
High and low pass filtering, convolution
Frequency domain filtering and analysis
Median filtering
Sobel/Roberts edge enhancement
Geometric transformations:
- magnification
- minification
- rotation
- polynomial warping with regular and irregular grids
Thresholding
Region of interest selection (any shape)
Color quantization: convert true-color images to pseudo-color

General Graphics

RGB, HLS, and HSV color systems
Mouse and cursor support for interactive output
Complete set of vector-drawn and device-specific fonts
Interactive annotation tool
Create an infinite variety of displays with lower level graphics primitives
Control color tables interactively
Create animations from graphics and/or images

Graphic Output Devices

Window systems: X, Microsoft Windows, Macintosh Quick Draw
PostScript: stand-alone and encapsulated (EPS), grayscale and color
Tektronix compatible terminals
DEC Regis (VT240, VT340)
Hewlett Packard PCL (laser printers) and HPGL (plotters) output
CGM Metafiles

GUI Toolkit

Create sophisticated graphical user interfaces (GUI) directly in IDL
Complete platform independence
Basic widget types include: base, sliders, buttons, labels, lists, text, and drawables
Compound Widgets: Create reusable widget interfaces

Signal Processing

Convolution: one-, two-, and three-dimensional
High and low pass filtering
Waveform generation
Signal editing
Fourier Transform: one to seven dimensions, any number of points
Spectral and time-series analysis

Statistics

Descriptive: mean, median, standard deviation, histograms
Probability distributions: binomial, gaussian, Student's t, chi square, F
Multiple and stepwise regression
Least-squares polynomial and exponential fitting
Cluster analysis: K-means, hierarchical, dendograms
Non-parametric statistics
Analysis of variance: one- and two-way classifications, equal and unequal sample sizes

Input/Output

Read and write virtually any data format
CDF, netCDF, HDF scientific file formats
Formatted I/O with default or user-specified formats
Transfer data efficiently with direct-access unformatted binary I/O
Save results with Save/Restore facility
XDR (eXternal Data Representation) support for portability
Standard graphics file formats:
- TIFF
- GIF
- PICT
- XWD
- SRF
- BMP
- JPEG

How to use IDL

To use IDL you will need to add the following to your .tcshrc file.

source  /usr/local/Standards/idl

To run IDL enter the following command:

idl

To access the IDL help system, you will need to run IDL then enter its help system. For example:

% setenv DISPLAY YourMachineName:0.0
% idl
IDL. Version 3.6.1 (sunos sparc).
Copyright 1989-1994, Research Systems, Inc.
All rights reserved.  Unauthorized reproduction prohibited.
Installation number: 2418.
Licensed for use by: Center for Coastal Physical Oceanography

IDL> ?
% Compiled module: MAN_PROC.
IDL>

IDL Frequently Asked Questions (FAQ)

The access the IDL FAQ click here HERE

Manuals Availability

Manuals are available from the System Administrator and/or the machine room book shelf.

Availability

IDL is available on the Suns, IBMs, and SGIs.

Press here to return to the User's Guide Menu.