Map difference data distribution device, map difference data distribution method, and vehicle navigation device

TL;DR: In this article, a map difference data distribution device is described, which consists of a difference data storage unit (12), a distribution processing unit (13), a prediction unit (231), a remaining capacity determination unit (233), and an over-capacity assessment unit (232a).

Abstract: The invention discloses a map difference data distribution device, a map difference data distribution method, and a vehicle navigation device. The map difference data distribution device is provided with a difference data storage unit (12), a distribution processing unit (13), a prediction unit (231), a remaining capacity determination unit (233), and an over-capacity assessment unit (232a). The prediction unit predicts whether undistributed difference group data is to be distributed on the basis of the distance between a user's residence and a data reference point among difference group data stored in the difference data storage unit, predicts from a dependence list the dependence-target difference group data of the difference group data that is to be distributed, and predicts the total data quantity thereof in relation to the next distribution period established by a difference update cycle. The distribution processing unit limits the data to be distributed in the next distribution period to a portion of the difference group data stored in the difference data storage unit on the basis of rules set in advance, while establishing a data amount that does not exceed the remaining capacity determined by the remaining capacity determination unit when the over-capacity assessment unit has assessed that the map data storage area is liable to be over capacity in the next distribution period.