| 摘要 |
PURPOSE: An index renewal method in a road network environment is provided to offer renewal costs reduction and search performance improvement effects by managing a mobile object with a road segment as a unit. CONSTITUTION: An input unit is input new position information to be renewed (S810). A search unit searches whether the new position information is stored in an existing memory grid (MG) or not (S820). An index renewal unit deletes position information stored in the existing MG and stores the new position information and renews an index if the position information is stored (S830). An MG search unit searches a grid of the existing MG capable of storing the new position information if the new position information is not stored (S840). [Reference numerals] (AA) Start; (BB) Can be stored in the MG?; (CC) Store in a DG; (DD) End; (S810) Input position information u to be renewed; (S820) New information = MG ?; (S830) Delete position information stored in the MG; (S840) Search a storable MG grid; (S850) Generate and store an overflow; (S860) Inspect the total number of entries of the MG and the number of used slots and stores them in a DG grid |
