5.4 Generating Personalized Tour Proposals Two services for generating personalised tour proposals are being developed in CRUMPET: a Route Agent and a Tour Agent. The Route Agent computes a path through a network of streets that includes two or more locations in the network. A typical application of the Route Agent is calculating and displaying the best or shortest route between two specified locations, e.g. from the user's current position to a certain destination. There are many different routing algorithms. In cases where street addresses are specified as either the starting or ending points of the route, an address geo-coding service is required. The task of the Tour Agent is much more complex, as it tries to suggest individual sight seeing tours according to the tourist's interest. Heuristic approaches are needed, because the underlying mathematical optimisation strategies are too complex (so called NP-hard) to actually compute an optimal solution.