Definitely an abreviation but I don't think it is part of a proper name but rather of the answer given above. Furthermore, the "Waitan" is considered to be in Puxi. My Shanghainese wife agrees with me on this (doesn't happen very often!) but I am never sure about anything in this life, perhaps some fellow translators might provide confirmation of this. Sorry Bin Li, computer offered no way to answer your last question, it didn't seem to want to let me add another comment under your answer, not sure why though.