Thanks for the info.  It appears that pyregion has added a new dependency 
on Pyrex or Cython.  I'll put this in the Python for Astronomers issue tracker 
so we won't forget to include this update.  BTW you might want to check into 
using Cython instead of Pyrex.  Generally speaking Cython is the preferred 
way to handle .pyx files since it is being very actively developed now.  Also, 
it looks like pyregion is supposed to build without Pyrex or Cython [1], but I 
guess that didn't work for you..

- Tom

[1] https://github.com/leejjoon/pyregion/commit/ff785c85464d4ef912931037beca8c47c7674e53

On Thu, May 31, 2012 at 2:30 PM, Shane Bussmann <rbussmann@cfa.harvard.edu> wrote:
> Hi Tom,
>
> I just wanted to let you know that I am upgrading my python packages
> (Enthought Python) using the installation instructions on the practical
> python for astronomers guide:
> http://python4astronomers.github.com/installation/python_install.html and I
> encountered an error when upgrading pyregion:
>
> error: unknown file type '.pyx' (from 'src/_region_filter.pyx')
>
> I googled a bit and found that installing pyrex first, and then installing
> pyregion fixes the error.  I don't know why this is the case, but it seems
> to work.
>
> -Shane