Detour Queries in Geographical Databases for Navigation and Related Algorithm Animations

In geographical databases for navigation, users raise various types of queries concerning route guidance. The most fundamental query is a shortest-route query, but, as dynamical tra c information newly becomes available and the static geographical database of roads itself has grown up further, more exible queries are required to realize a user-friendly interface meeting the current settings. One important query among them is a detour query which provides information about detours, say listing several candidates for useful detours. We have proposed e cient algorithms for enumerating meaningful detours [6, 14]. In this paper, we rst review our algorithms for the static case, and discuss their extensions to incorporate dynamical information in an e cient manner. Also, in connection with the user interface part, animation of the proposed algorithm is performed, and its prototype version is made public via WWW. In a more general setting, we discuss data mining of this rapidly growing geographical database as an interesting target to derive useful information from vast geographical data. Applications of this data mining cover a broad class of real-world problems such as urban planning, environmental assessment, social welfare, facility management, disaster prevention, etc., from the governmental standpoint and, marketing, customer management, etc., in the business world. This paper investigates the road network for navigation in the geographical database from this point of view, and proposes how to obtain a nice collection of candidates satisfying user requirements by our clever enumeration approach for detours and how to present them to users by visual interfaces.