How do I get the precise location (house/address)....

Of a cellphone number? Using open source methods (google etc).

1) Call the number
2) Ask ``What is your precise location (house/address)?''
3a) Note to yourself that Google's primary service, a search engine, is decidedly not open-source.
3b) Note that were there not a moral restriction on a certain redirection, it would certainly be in play.