An apparatus and method for rapid translation of geographic
latitude and
longitude into any of a number of application-specific location designations or location classifications, including street address, nearest intersection, PSAP (Public Safety Answering Point) zone, telephone rate zone,
franchise zone, or other geographic, administrative, governmental or commercial division of territory. The speed of translation meets call-setup requirements for call-
processing applications such as PSAP determination, and meets caller response expectations for caller queries such as the location of the nearest commercial establishment of a given type. To complete its translation process in a timely manner, a memory-stored
spatial database is used to eliminate
mass-storage accesses during operation, a spatial indexing scheme such as an R-tree over the
spatial database is used to locate a caller within a specific rectangular area, and an optimized set of point-in-polygon algorithms is used to narrow the caller's location to a specific zone identified in the
database. Additional validation
processing is supplied to verify intersections or street addresses returned for a given
latitude and
longitude. Automatic conversion of
latitude-
longitude into coordinates in different
map projection systems is provided. The memory-stored
database is built in a compact and optimized form from a relational
spatial database as required. The R-tree spatial indexing of the memory-stored
database allows for substantially unlimited
scalability of database size without degradation of
response time. Maximum performance for database retrievals is assured by isolating the retrieval process from all updating and maintenance processes. Hot update of the in-memory database is provided without degradation of
response time.