Routing method for computing routes over uncertain geo-spatial data whereby only upon visiting the geographic entities it can be determined whether the needed service or product is actually provided and is adequate. When dealing with uncertain data, the returned route may need to go via several entities of the same type. Another routing method consists of finding an efficient and effective route from a starting point to an ending point going trough a predetermined number of objects, wherein each object represents a geographical entity of a unique type, and each object is selected from a distinct set of similar objects.