Final answer:
The topological data model is used in computer science and GIS to represent spatial relationships. The key properties maintained by this model include connectivity, adjacency, and direction, while elevation is not a key property.
Step-by-step explanation:
The topological data model is used in computer science and geographical information systems (GIS) to represent spatial relationships between geographic features. The key properties maintained by this model include connectivity, adjacency, and direction. However, elevation is not a key property maintained by the topological data model.