Advantages of NCL over IDL:

1. Some non-NCAR people may not have or may not be able to afford IDL.
   (NCL binaries can be provided by us free of charge, as part of a
   post-proc package.

2. Support for NCL is in-house and 'immediate'. IDL support costs HAO
   $$, and is not available on an individual user baseis. Support for
   NCL is guaranteed on all NCAR platforms.

3. NCL users (e.g. hao) can have some influence on the development of
   the language itself, e.g., commonly used customized capabilities can
   be incorporated directly into NCL.

4. NCL would allow closer collaboration with other divisions e.g.
   CGD, ACD, WACCM, etc.

5. If we do this in IDL only, we will not benefit from Sylvia's expertise
   is web site development as well as NCL), nor from continued development
   by CGD.


Advantages of IDL over NCL:

1. A lot of code already exists in IDL -- why should it be converted to NCL?
   Most users are already familiar with IDL and IDL fulfills their needs.

2. IDL image display and processing capabilities are more developed than
   NCL. Also, there is some 3d volume rendering in IDL that is not currently
   available in NCL.

3. Online documentation is better, easier to use,  in IDL.