Subchapters:

External libraries

The popularity of IDL made it a development language in a lot of domains (Medical imaging, Meteorology, and Astronomy). It's possible to download some free packages and use it to, for example, analyze spectra of IUE or images of HST.

In the normal use, IDL doesn't know where the libraries are. You have to add the location path to the set of path in witch IDL will look for procedures files.

The WWW address where those package are available are in the second part of the references .

The Add_path command

To have access of the list of those package (only at IAG, ask your system manager to install them if needed, a copy of our add_path is here ) , just do:

IDL>add_path,/help

In this example, there are 15 different libraries available. If you have to use both the astro and the esrg libraries, do:

IDL>add_path,/astro,/esrg,/verbose
/usr/local/rsi/idl_5/lib/hook:/usr/local/rsi/idl_5/lib/obsolete:/usr/lo [...]

Using the /verbose keyword, IDL print all the searching paths, including the new added ones.

The astro package allows you to work with fits files, to transform coordinates, to unred observational data, etc.
With the esrg library, you can use the tvim and confill procedures to display images.

You can also add a personal path, using the path='my_IDLdirectory' keyword.

All those package are in the directory /usr/local/rsi/contrib/Just have a look at them.

Help in the contrib packages

The procedures accessible with the external packages don't have help pages in the idlhelp hypertext help tool. Anyway, most of them have a documentation in the header of the procedures files themselves that you can access under idl.

        IDL>add_path,/astro
        IDL>doc_library,'fits_read'
              ----- Documentation for /usr/local/rsi/contrib/astro/pro/fits/fits_read.pro -----
              *NAME:
                      FITS_READ
              *PURPOSE:
                      To read a FITS file.
              *CATEGORY:
                      INPUT/OUTPUT
              *CALLING SEQUENCE:
                      FITS_READ, filename_or_fcb, data [,header, group_par]
              *INPUTS:
                      FILENAME_OR_FCB - this parameter can be the FITS Control Block (FCB)
                              returned by FITS_OPEN or the file name of the FITS file. If
                 [...]