Concepts and Models of Space > Geographic Applications > Abstraction
Assume 2-D and a GIS application, basic abstractions that need to be modeled in a systema are:
- Modeling single objects in space: cities, forests, or rivers single objects
- Modeling spatially related collection of objects:
- partitions
- networks
- coverage
- nested partitions
- digital terrain models
In GIS, geographic information is handled in thematic layers or theme layers. The relationship between theme and geographic objects satisfied the following definitions:
- theme = {geographic_objects}
- geographic_objects = (description, spatial_part}| (description,
{geographic_objects}
The definition of geographic objects is recursive with two main distinctions: while simple spatial objects have a description and a spatial part, complex spatial objects include a description and a set of geographic objects.
