Graphics Reference
In-Depth Information
Figure 13-8:
Adding interactions enables the viewing of details for a
single state. Here, shipments in and out of Texas by value of goods are
shown, revealing a relative imbalance of flow with other Southern states.
Use of curved links reduces overlap and expresses flow in a clockwise
direction.
Route Patterns
Routes
can be an important dimension of spatial networks. Sometimes you
may simply want to find the optimal path between two nodes, as in the
subway map example shown earlier in
Figure 13-2
.
Other times you may be
looking for meaningful patterns in paths traveled across the entire network.
In some cases, those paths may have a spatial dimension in the data.
For example, transportation vehicles for a postal delivery service may use
a global positioning system (GPS) to record tracks followed over time and
upload them to a central database, contributing to information about
frequency of routes traveled and efficiency of routes at various times of
day. Other times, just an origin and destination may be available for each
trip. For example, the same postal delivery service may record the time and
location of pickup and delivery of each item, including every distribution
center along the way. This would contribute to statistics on the number and
type of items transported between each location, and time taken to reach
each stop. Analyzing patterns in route data can provide valuable insights
