Databases Reference
In-Depth Information
Figure 5-11. Elements in the Global Post network
Over time, the delivery routes change.
Figure 5-12
,
Figure 5-13
, and
Figure 5-14
show
three distinct delivery periods. For any given period, there is at most one route between
a delivery base and any particular delivery area or segment. In contrast, there may be
multiple routes between delivery bases and parcel centers. For any given point in time,
therefore, the lower portions of the graph, the individual subgraphs below each delivery
base, comprise simple tree structures, whereas the upper portions of the graph, made
up of delivery bases and parcel centers, are more complexly structured.
