The data models in geographic databases or the Spatial data model allows the geographic features in real world locations to be digitally represented and stored in a database so that they can be presented in a map form, and can also be worked with and manipulated to address spatial analysis and decision making. GIS data models can broadly be either vector data model or raster data model based on the data they use to represent and store.
Spatial data modeling is a precondition and key to the design and realization of spatial database which provides means for spatial data organization. The integrality and consistency of geographic data rely on how the data model represents, stores and manages the GIS data.
The representation of data is done at conceptual level. The conceptual level defines the entities, their properties and relationship between entities, which are important for a particular application domain. The conceptual model is translated into a set of constructs supported by the target database management system (DBMS) at the logical level. At physical level, data are mapped onto the physical structure of the DBMS.
Any GIS data model is implemented in layers. Data is organized by layers, themes, with each layer representing a common feature or its subsets. The data model represents a set of guidelines to convert the real world (called entity) to the digitally and logically represented spatial objects consisting of the attributes and geometry. The attributes are managed by thematic or semantic structure while the geometry is represented by geometric-topological structure.