Each pixel represents quite a lot of area so aliasing probably isn't coming into it.
Bakersfield has a bunch of buildings (which lines up with the theory in my other post in this thread). It looks like imported land parcels make up a lot of the data in the Fresno blob:
Bakersfield has a bunch of buildings (which lines up with the theory in my other post in this thread). It looks like imported land parcels make up a lot of the data in the Fresno blob:
http://www.openstreetmap.org/#map=16/36.7805/-119.9009&layer...
(Probably a good idea to turn off the data layer there before zooming out)