Patent ID: 8245146

Claim:
A map display device comprising: an image display unit; a storage medium configured to store map data divided into multiple unit areas; and a control circuit configured to indicate a map on the image display unit according to the map data, wherein the map data includes multiple name records respectively corresponding to multiple names to be indicated in the map, each of the multiple name records includes information specifying a character string of a corresponding name and information specifying an indication range of the character string in the map, and the control circuit includes: an updating unit configured to update a partial unit area in the multiple unit areas; an extracting unit configured to extract a pair of same character strings, which are overlapped and to be indicated in the vicinity or a boundary between an area, which is in the map and is not updated by the updating unit, and the partial unit area, which is updated, with reference to the multiple name records, after update by the updating unit; a prohibiting unit configured to prohibit indication of one of the pair, which is extracted by the extracting unit, in the map; and a prohibition canceling unit configured to, after the prohibiting unit prohibits indication of one of the pair, which is extracted by the extracting unit: search a character string, which does not overlap with a character string of an other name when indicated in the map and is not indicated close to a character string of a same name when indicated in the map, from a character string corresponding to a name record, which is prohibited from indication due to overlap with a character string before update by the updating unit, in the multiple name records; and cancel prohibition of indication of the found character string.