Data in rotated grid coordinates

[Javier G. Corripio]

Dear Nina,

I've burnt half my brain cells with those rotated grids, so if you make grads understand them, please
let me know.

In the meantime, in order to display a region of interest or to extract data from one or several points
I have written an IDL routine to find the equivalent geographical coordinates of the rotated grid.  It is
not fully tested, so use it with care.

The code and a pdf with explanations are  at http://www.arolla.ethz.ch/software.html  (sixth bullet
from the top).

All the best,

Javier