Navigation server, navigation client and navigation system

A navigation system including a navigation server and a navigation client, wherein

• the navigation server comprises
• a navigation server storage device configured to store a set of topics for each of a plurality of areas and a correlation rule defining an order of the topics contained in the set,
• a first server arithmetic processing element configured to
• recognize a designated area in a navigation client based on a communication with the navigation client as a mobile station,
• retrieve a plurality of topics in the designated area and a correlation rule, based on probe information, among the plurality of topics from the navigation server storage device, wherein the probe information represents a time series of a position of the navigation client or factors affecting running of a vehicle detected in the navigation client, and
• generate guide information for guiding the vehicle in an order of the plurality of topics transmitted to the navigation client, and
• a second server arithmetic processing element configured to
• assist, by transmitting the plurality of topics and the correlation rule retrieved by the first server arithmetic processing element to the navigation client, the navigation client in designating a topic group that is at least a part of the plurality of topics and in outputting guide information for guiding a plurality of places corresponding to at least a part of the topic group in an order defined in accordance with the correlation rule, and
• the navigation client comprises an input device, an output device, and a client storage device storing client map information, and further comprises
• a first client arithmetic processing element configured to make a navigation server recognize a designated area input through the input device based on a communication with the navigation server, and
• a second client arithmetic processing element configured to
• receive the plurality of topics in the designated area and the correlation rule among the plurality of topics from the navigation server, and
• output the plurality of topics to the output device, wherein buttons of the output interface respectively represent the plurality of topics arrayed in the order defined in accordance with the correlation rule, wherein the first client arithmetic processing element is further configured to
• recognize the topic group that is at least a part of the plurality of topics designated through the input device, and
• output guide information to the output device, the guide information being for guiding the plurality of places corresponding to at least a part of the topic group in the order defined in accordance with the correlation rule.