GURPS Magic Spell Charts (2006)

From the front page:

These charts are a visual representation of the relationships between the hundreds of spells listed in GURPS Magic. They not only reduce the work required to determine the prerequisites for a spell, but also reveal the underlying organization of the colleges. For each college, they show how far can one progress at each level of Magery; which spells are central, prerequisites for most of the other spells in the college; and how much overlap there is with other colleges. The simple, open format allows for further customization. Color the boxes to show which spells a mage knows and instantly see which ones he is eligible to learn.

This new vector graphics version is less han 10% the file size of the old edition; Also, all known errata to date have been corrected.