[Proj] proj deployment question

[jjholt at hiwaay.net]

I have created a VC++ COM component that our application uses for projection
services. It links with proj as a static Win32 library to do the actual projection.

It works great, but I'm wondering about deployment issues. Normally I thought
the proj library requires some files - eg "nad" directory and maybe others.
However my component seems to work even on systems without any other proj files
on it.

We only do relatively simple stuff - geographics to/from UTM, geographic to from
Mercator, and UTM zone to zone. Is that why? Maybe "nad" is only needed for
"datum shifts"? I don't know what a "datum" is, let alone how to shift one :-)

I suppose another way to put it is: what capabilities won't work without
external proj files?

Thanks,
Jeff