1. A data processing system for managing geographic identifiers stored in a database, the geographic identifiers each identifying a respective geographic feature displayed on a surface map space partitioned by a mosaic of non-rectilinear shaped cells, the data processing system comprising: an accessing module for accessing a geographic look-up table and an index for the geographic look-up table, the geographic look-up table and the index being stored in the database; an identification module for identifying, from the index, stored row identifiers associated with a subset of the mosaic of non-rectilinear shaped cells; and a retrieving module for retrieving, from the geographic look-up table, stored geographic identifiers associated with the identified stored row identifiers.