Patent ID: 6917879

Claim:
A computer readable memory containing computer readable instructions, comprising: an instruction unit to store map data including road network data and landmark data in a database; an instruction unit to search for a route from a departure point to a destination point from the road network data stored in said database; an instruction unit to divide the route into a departure area, a destination area, and an intermediate area, wherein the departure area is a route area from the departure point to a first target point, the destination area is a route area from a last target point to the destination point, and the intermediate area is a junction area excluding the departure area and the destination area from the route; an instruction unit to set a mask having a size several times a road width of advance direction of the junction area; an instruction unit to extract the road network data corresponding to the mask from said database as a route network extraction area; an instruction unit to analyze a road pattern of the route by referring to the road network data; an instruction unit to obtain road pattern data as the analysis result; an instruction unit to generate route guidance information of the route using the road pattern data and the landmark data along the route; and an instruction unit to present the route guidance information by speech.