(The NCAR Command Language (NCL), a product of the Computational & Information Systems Laboratory at the National Center for Atmospheric Research (NCAR) and sponsored by the National Science Foundation, is a free interpreted language designed specifically for scientific data processing and visualization.

NCL has robust file input and output. It can read and write netCDF-3, netCDF-4 classic, netCDF-4, HDF4, binary, and ASCII data. It can read HDF-EOS2, HDF-EOS5, GRIB1, GRIB2, and OGR files (shapefiles, MapInfo, GMT, Tiger). It can be built as an OPeNDAP client.

NCL visualizations are world class and highly customizable.

Both NCL and NCAR Graphics are released as one package in source code or pre-compiled binary format. See the download page for more information. NCAR Graphics still has its own home page.

The NCL User Guide is an excellent beginner's guide to NCL language basics, with a step-by-step tutorial on writing NCL scripts for reading/writing files, doing computational analyses, and generating publication-quality graphics.