Most modern supermarket chains are organized in such a way that location data should be available (or at least calculable). To assert that there is no "system" to a store's layout and that employees know through "experience and gut-feeling" means that this retailer was not conforming to industry norms or was just not a very large retailer. All supermarkets have some sort of product taxonomy, categories and subcategories, that influence the macro-placement of a product within the store. This discipline is known as "space planning", where large categories are placed within the foot print of a store's layout. Within the category placement, stores use "planograms", which are shelf-by-shelf layouts of which products go where, how many facings they have, how much footage is designated to the sub-category, etc. While its true that workers for the most part know the locations of items by experience, this experience is informed by their ever growing knowledge/intuition of this taxonomy. (Usually, products are organized by aisle in the backroom when the delivery comes in; workers are simply taking groups of products that have already been organized out to the floor). The planograms themselves are usually stored in a database, and this data could be cross-referenced with other common data sources (product, pricing, etc.) to determine store location.