Compare Zambia with Mali, another landlocked African country. GIS can be very useful in helping to understand many different types of landscapes and the problems associated with spatial factors. This type of GIS operation demonstrates the potential complicated geopolitics of landlocked nations, in this case both of which have a large number of neighbors relative to most non-landlocked nations, making significant international political and economic concerns for maintaining good relations. It is a valuable component of GIS and is useful in a very wide range of applications. Topology offers a number of advantages and contributions to geographic data and GIS, which are depicted in figure 4-6 and described in the following.
Topology provides length, distance, perimeter, and area.
Image 1 shows East Africa and the database resulting from topological calculations. A query asking which nations border Kenya will be replied with Tanzania, Uganda, Sudan, Ethiopia, and Somalia, as read from the topology tables. Image 1 shows the polygon adjacency connections from Tanzania through Kenya to Somalia. All of these attributes are easily determined because of topological connections and database queries.