A method for navigation includes storing map data on a server, the map data including
vector information delineating roads in a map. A portion of the vector information
corresponding to an area in which a user of a mobile client device is traveling
is downloaded from the server to the client device. Approximate position coordinates
of the user are found using a location providing device associated with the client
device and are corrected in the client device, using the downloaded vector information,
so as to determine a location of the user on one of the roads in the map. A navigation
aid is provided to the user of the client device based on the determined location.
