In the February 28th, 2005 strip Chris gives a Danville zipcode, but in the New Years' strip he gives a map that exactly matches Palo Alto--- so exact in fact that I presume he got it from the same place I got mine: Google Maps.

(The fact that this is clearly Google Maps or Mapquest source material makes me feel slightly less bad about violating the clearly marked copyright in the upper right corner of the strip.)