[yvolution]

No where else has more sky scrapers than Shanghai and Beijing, which easily affects your GPS signal.

[cbr]

If you mean buildings over 100m, then no:

    1 	Hong Kong
    2 	New York City
    3 	Tokyo
    4 	Dubai
    5 	Shanghai

Beijing is #20.

http://en.wikipedia.org/wiki/List_of_cities_with_most_skyscr...

[archangel_one]

I suspect that Tokyo might well have more. Anyway, the loss of accuracy in such a case wouldn't cause a consistent effect like this - it's normally not in a consistent direction and generally doesn't put you off by so far.