Topological relations
The concept of topology is a common approach of human's mind to determine the reality. The visual perception is topological.
When people look at landscapes, or when they consult a map or a plan, their immediate perception is global. Objects such
as
buildings, forests, agglomerations are perceived in the whole context. The term of neighborhood is implicit:
There is a river traversing the agglomeration, M. Dupond's parcel borders on M. Schmidt's parcel.
That means, because of the perception of geographic space, topology is the collective of all the detected relations.
This
allows observers to locate objects in relation to other objects. Which object is next to another object? The "neighborhood"
is therefore a spatial notion.
The concept of topology is a fundamental element in spatial analysis. Without it, it would be impossible to extract information
about the neighborhood or about a river's drainage direction from the database. The concept of topology is known in several
disciplines.
Mathematics gives a rigorous definition: "Propriétés des êtres géométriques subsistant après une déformation continue,
et qui
fait abstraction de la notion de distance". Sometimes it's also called: Geometry without metrics. In other disciplines,
the
meaning of topology is broader. In social sciences, topology is an arrangement, a configuration of people and their relations.
In GIS topology is used to get information about the proximity between the elements. The topological relations in this
context are the adjacency, the connectivity, the inclusion and the intersection.