1. A portable scanning device for scanning a product item, the product item having visible information relating thereto and a plurality of tags disposed thereon, each tag encoding data on an identity of the product item and the location of the tag on the product item, the scanning device comprising: a depressible trigger for operation of the scanning device; a sensor for sensing the data encoded by at least one tag by scanning the at least one tag with a moving sensing beam within a patch containing the product item and by scanning the patch with a moving sensing beam within a scan volume upon depression of the trigger; and a processor for determining, from the sensed data, product identity data indicative of the identity of the product item and location data indicative of a location of said at least one tag on the product item.