Patent ID: 7206660

Claim:
A navigation apparatus comprising: a first storing device for storing original data for a navigation based on a predetermined format and including map data, in such a manner that an empty area exists on the predetermined format in each of a plurality of units of processing objects for a predetermined kind of navigation processing, wherein each unit of processing object is a unit of the original data; a second storing device for storing difference update data representing a data portion for the navigation that is updated with respect to the original data as a standard; a re-writing device for generating updated data based on the format and including the original data and merge data, by re-writing the merge data at least partially into the empty area corresponding to the merge data, the merge data defining a relationship of the difference update data stored in said second storing device with respect to the original data stored in said first storing device for said each unit of processing object; and a processing device for (i) making access, for said each unit of processing object, to the original data and the merge data in the updated data, and (ii) if the accessed data is the merge data, then also making access to the difference update data, the relationship of which is defined by the merge data and which is stored in said second storing device, and (iii) performing the navigation processing on the basis of the accessed original data and the accessed difference update data.