The vector model stores features using an implicit representation of the world. A feature is represented as a collection of begin and end points used to define a set of points, lines or polygons which describe the shape and size of the feature. The vector model is particularly useful for representing highly discrete data types such as roads, buildings, boundaries and the like. The vector model supports the encoding of topological relationships into the features allowing the efficient storage of adjacency, contiguity, connectivity and direction. Using the topology information a GIS can store complex objects more efficiently, find adjacent areas, and model flows through a network.
Most corporate databases contain various types of geographic references.
While the geographic features stored in a GIS are all encoded with explicit geographic references in the form of a set of coordinates, most other data sets contain more subtle and implicit forms of geographic references such as, addresses, place names, zip codes, phone numbers, asset number, etc, or just indirect references to geography such as 500 meters down the road from city hall. The power of GIS lies in its ability to link all of these implicit types of geographic references to explicit locations stored in the GIS and therefore incorporate them into the GIS and use the associated data in its query and analysis functions.