A communication type navigation apparatus can communicate with a server device
via a communication path. The navigation apparatus requests route search, and the
server device executes route search to produce route information of a searched
route. Then, the meshes necessary to travel along the searched route are determined,
and the navigation apparatus obtains necessary mesh data from the server device.
The navigation apparatus may request newer mesh data to the server device based
on the updating information of the mesh data. By appropriately determining the
mesh data to be and not to be downloaded from the server device, the communication
cost necessary for obtaining the mesh data can be saved.
