Patent ID: 7542847

Claim:
A map display device having a corridor function for partially clipping map data, that map data including a plurality of minimum units, the minimum unit being defined as a smallest unit to be clipped from the map data, the device comprising: a control unit configured to specify one of the minimum units of the map data, the one of the minimum units including a reference position; define four sections within the specified one of the minimum units by evenly dividing the specified one of the minimum units lengthwise and breadthwise; specify one of the four sections within the specified one of the minimum units, the specified one of the four sections including the reference position; determine a sequence of enlarging a region to be clipped based on the specified one of the four sections, the region including the reference position at a central part of the region; clip a part of the map data corresponding to the region; and store the clipped part of the map data in a memory; and a display unit configured to display a map of the region based on the clipped part of the map data.