Second, from the general view, we would like to have a general representation of a multimodal transport network
where the basic elements are nodes and links. This is described in figure 1. As we mentioned before, there are two
kinds of nodes in a supernetwork: physical nodes which represents locations and have X, Y coordinates as necessary
attributes, and event nodes which represent the arrival and departure events at certain stops or stations. The latter
nodes have event type, event time and service related factors (e.g. bus route, but trip, stop sequence) as necessary
attributes. Only physical links have distance, time, speed, monetary costs, emission, quality and general cost as
necessary or possible attributes.