Abstract: In some implementations, a method performed by data processing apparatuses includes receiving original map data for a digital map of a physical space, receiving item location data that represents item scans that have been performed by mobile devices in the physical space, and determining that a discrepancy exists for a fixture in the physical space, based at least in part on a comparison of the original map data and the item location data. In response to determining that the discrepancy exists, map data is generated that corrects the discrepancy for the fixture, and a corrected digital map is provided that replaces the original map data with the corrected map data.