Working example of algorithm presented in last post can be found here.
It shows map with some of my home town's bus stops. User can drag marker with and then second marker shows nearest bus stop location. Also number of closest busstops to be found can be changed with value of "number" get parameter. Additional parameters are "treedepth" and "showchecked". The former is int value which determines depth for separation lines presentation. The latter is bool value indicating whether to mark points checked during search or not.