A system for updating, enhancing and/or refining a geographic database is disclosed. The system uses a plurality of data collecting sensors, each of which is installed in a separate one of a plurality of vehicles, each of which travels on roads in a geographic region. Each data-collecting sensor provides outputs indicative of the sensing of one or more features in the geographic region as the vehicle in which it is installed travels. A computer program process compares the outputs of the data collecting sensors to previously obtained data that represent the physical features, determines the significance of the comparisons, and updates, enhances, or refines the data in an existing geographic database accordingly. Data that have been updated, enhanced, or refined, are provided back to end users.