Map updating systems, methods, and programs

A mobile device, comprising:

• a map data storing unit that stores a plurality of pieces of map structuring data;
• a communication unit that receives instruction data from a map updating system, the instruction data used for updating a pre-update piece of map structuring data among the stored plurality of pieces of map structuring data to a post-update piece of map structuring data, the instruction data identifying, in units of bytes, a portion of the pre-update piece of map structuring data to be updated and a post-update data content;
• and
• a controller that updates the pre-update piece of map structuring data to the post-update piece of map structuring data according to the instruction data by updating, in units of bytes, the portion of the pre-update piece of map structuring data to be updated identified by the instruction data so that the portion includes the post-update data content identified by the instruction data.