Patent ID: 8321375

Claim:
An update method performed by a server and a control device of a navigation apparatus for updating search data used in the navigation apparatus, the update method comprising: providing, by the server, initial search data comprising search tree data having a tree structure and a plurality of sets of initial substance data specified based upon the search tree data, wherein the initial substance data include facility information; providing, by the server, update search data comprising a set of update substance data separately from the initial search data without updating a set of the initial substance data in the initial search data or adding a set of initial substance data to the initial search data, wherein the update substance data are provided without any search tree data, have a non-tree index as a search key that does not require any search tree data, and include facility information; and executing, by the control device, a substance data search by using a tree-based search based on the search tree data of the initial search data and an index-based search using the non-tree index of the update substance data, wherein upon obtaining the update search data from the server, the navigation apparatus stores the obtained update search data into a storage device separately from the initial search data; the control device of the navigation apparatus transmits, to the server, information indicating a range of search data to be updated; if update search data are available over the range of search data to be updated indicated in the received information, the server provides the update search data over the range to the navigation apparatus; and in correspondence to each character entered via an input device of the navigation apparatus with which a search key can be entered one character at a time, a search executed by using the search tree data is advanced, the character is compared with the non-tree index, which is contained in each of a plurality of sets of update search data stored in the storage device, and a non-target flag is added to each set of update search data which has been determined not to be a search target based upon comparison results, wherein the non-target flag indicates that each set of update search data that includes the non-target flag is not to be compared in a subsequent index-based search.