About this document

What it is

This document provides a practical introduction to NCL (the NCAR Command Language). NCL is a programming language designed specifically for the analysis and visualization of data.

This document is integrated into a very large NCL documentation website. Many links in "Getting Started Using NCL" (GSUN) take you elsewhere in this larger website.

Who it's for

This document is aimed at users with little or no experience with NCL, although more advanced users may find it useful as well. Familiarity with the principles of programming languages is assumed. Familiarity with at least one self-documenting and network-transparent data format such as netCDF or HDF is highly desirable. If you are not familiar with such a data format, see the netCDF User Guide.

What's in it

The heart of this document is the "Learning NCL by example" chapter. In that chapter some NCL plotting functions and procedures are introduced that provide a basic interface to the plotting capabilities of NCL. Full consulting is provided on these functions and procedures, and reported bugs will be fixed.

After reading the "Introduction," progressing through the examples chapter and reading the "Basics" chapter, you will have a solid understanding of the NCL basics. You'll want to read the chapter "Going beyond the basics" in this document to learn about the full power of NCL.

The appendix documents the plotting functions and procedures used in this document, provides some advanced NCL examples, and lists some useful URLs, and the glossary defines terms that you may encounter in this document.

Conventions used in this document

  • Bold font is used for command names, options, filenames, pathnames, directories, and so forth.
  • Italic font is used for variables for which you must enter a value and for optional arguments. The names of documents are also shown in italic font.
  • A fixed width font is used for all program source code and screen displays.

Where to get help

Email lists

Email lists are available for NCL users who want to discuss problems and solutions with other users. To find out more about these groups, go to the URL:
These email lists give NCL users a chance to share information and ideas among themselves and to bring up NCL issues that are of concern. NCAR personnel will not necessarily read or respond to correspondence on a regular basis. The intended use is solely for the NCL software user community. To see an archive of email messages, go to the above URL.

Comments and suggestions

We welcome your comments and suggestions. They help us understand the needs of NCAR Graphics software users, and they influence the evolution of the package and the direction of our development efforts. If you have any enhancement requests or would like to report a possible bug, please contact:
Electronic mail:
Mary Haley

Postal service mail:
NCAR Graphics Group/Software Support
National Center for Atmospheric Research
P.O. Box 3000
Boulder, Colorado 80307-3000