Also in Figure 22-4 is the entity class Path Composition. This is the fact that a (shorter) Path may be a component in one or more other (longer) Paths. This allows us to recognize that the Path from the airport to the hotel is made up of many component Paths. This allows for the complete description of a longer route, seen from a high level, to be decomposed into as much detail as necessary to fully describe it.
It is also how a Roadway Path may be assembled from a set of Alignment Nodes and the Roadway Paths linking them together.
A second way to collect multiple Paths together is to aggregate them into Networks. Where a single string of Paths can connect to create a larger Path through a set of Path Compositions, (the set of ...