Topology is a data structure often used in GIS. Topology is the stored relationships between map features. When topology has been created (such as in an ARC/INFO coverage), the file would “know” its position, “know” what is around it, “understand” its environment by virtue of recognizing its surroundings, and “know” how to get from A to B. Topological relationships are stored in a series of relational databases. Each database stores information about a feature.
Example of Topology
A database would store the following information about each individual arc:
- Number of the arc
- Beginning node number
- Ending node number
- Polygon to its left
- Polygon to its right
In this way, each node, line, and polygon could be defined by its neighbors and what it is connected to.