Custom Projection

[Abe Gillespie]

Hello all,

Forgive my ignorance on the subject - is there a way to define a
custom projection such that it simply applies a rotation to the map?
For instance, instead of the map being oriented with the top as north,
I need to orient it in a "you are here" fashion.  I want to put the
entrance of a building at due south.

First, in general, can this even be done?  What I mean to say is are
projections even used in this fashion?  Second, if it can be done, how
does one go about defining a custom projection?  Can you fire up
ArcGIS and use the GUI?  Are there command line tools?

Thanks for any help.
-Abe