The format and organisation of the database into user defined attribute tables as well as the structure of layers and networks. The schema allows us to organise data in a logical manner. Spatial information may be considered as having a graphical component. This refers to the way in which data is systematically organised within a data-base. For example, the lowest structural level consists of individual point, line and polygon features.
Topology is formed during polygon formation.
This refers to the hardware used for interaction with the computer and the textual and graphic displays presented to the operator.