Navigation apparatus

A program product stored in a non-transitory computer readable storage medium comprising instructions for execution by a computer, the instructions including a computer-implemented method for a navigation apparatus providing route guidance to a vehicle using road data indicating links and end nodes of the links relative to roads,

• the navigation apparatus including
• (i) a ready-made road data storage portion in which existing road data relative to existing roads on a ready-made map is stored, and
• (ii) a learned road data storage portion in which road data relative to learned roads is stored,
• the instructions for implementing:
• a step of detecting a new learned road, which is not stored in the ready-made road data storage portion, based on a traveling locus from a withdrawal-point where a running position of the vehicle withdraws from a withdrawal existing link of a withdrawal existing road stored in the ready-made road data storage portion to a return-point where the running position of the vehicle returns to a return existing link of a return existing road stored in the ready-made road data storage portion;
• a step of generating learned road data of the new learned road, the learned road data indicating (i) a learned link of the new learned road and (ii) first and second learned end nodes of the learned link of the new learned road;
• a step of defining each of the withdrawal existing link and the return existing link as a base link while defining each of the withdrawal-point and the return-point as a connection point;
• a step of generating, based on road data relative to the base link stored in the ready-made road data storage portion, auxiliary link data with respect to each connection point of the base link, the auxiliary link data indicating
• (i) a first auxiliary link, which connects the each connection point with one of two end nodes of the base link, and two auxiliary end nodes of the first auxiliary link and
• (ii) a second auxiliary link, which connects the each connection point with an other of the two end nodes of the base link, and two auxiliary end nodes of the second auxiliary link;
• and
• a step of recording, with respect to the new learned road, the learned road data and the auxiliary link data in association with each other in the learned road data storage portion.