Hierarchical route maps for efficient navigation

One of the difficulties with standard route maps is accessing to multi-scale routing information. The user needs to display maps in both a large scale to see details and a small scale to see an overview, but this requires tedious interaction such as zooming in and out. We propose to use a hierarchical structure for a route map, called a "Route Tree", to address this problem, and describe an algorithm to automatically construct such a structure. A Route Tree is a hierarchical grouping of all small route segments to allow quick access to meaningful large and small-scale views. We propose two Route Tree applications, "RouteZoom" for interactive map browsing and "TreePrint" for route information printing, to show the applicability and usability of the structure. We conducted a preliminary user study on RouteZoom, and the results showed that RouteZoom significantly lowers the interaction cost for obtaining information from a map compared to a traditional interactive map.