Abstract: In some implementations, a method performed by data processing apparatuses includes receiving, from a requestor device, an item location request for an item. Map information is received for a mapped space in which the item is located. Item location coordinates are received corresponding to locations within the mapped space at which the item has been previously selected or scanned. The item location coordinates are mapped with respect to the mapped space, and a plurality of clusters are determined for the item location coordinates. For each cluster, a representative location of the cluster is determined. One of the clusters is selected, based at least in part on its representative location, and an estimated location of the item is provided to the requestor device, based at least in part on the representative location of the selected cluster.