question: public boolean isUndefined ( ) { return ( lat == 0 && lng == 0 ) || lat < - 90 || lat > 90 || lng < - 180 || lng > 180 || Double . isNaN ( lat ) || Double . isNaN ( lng ) ; }
target:  The most common undefined LatLong's come from class Location, where they produce dummy Location objects for storing the timezone. 