DEVICE AND METHOD FOR SPECIFYING ALTITUDES OF TUNNEL ENTRANCE AND EXIT, COMPUTER PROGRAM FOR SPECIFYING ALTITUDES OF TUNNEL ENTRANCE AND EXIT, AND RECORDING MEDIUM FOR RECORDING THIS COMPUTER PROGRAM

摘要

The present invention provides a system for automatically specifying tunnel entrance and a method therefor. The method includes a target entrance selecting step for selecting, from a map data storing portion, a target entrance for specifying an entrance elevation of a tunnel; a target road link assigning step for assigning, from the map data storing portion, a road link, which includes the target entrance, as a target road link; a corrected point extracting step for extracting a certain point as a corrected point, the certain point located along the target road link and away from the target entrance outwardly of the tunnel by a predetermined distance; a corrected point elevation specifying step for specifying an elevation of the corrected point as a corrected point elevation; and a first target entrance elevation specifying step for specifying the corrected point elevation as a first elevation of the target entrance.