Bentley Map's persistent topology is based on Oracle’s topology model:

The basic elements in a topology are nodes, edges, and faces.

A node, represented by a point, can be isolated or it can be used to bound edges. Two or more edges meet at every non-isolated node. A node has a coordinate associated with it that describes the spatial location for that node.

An edge is bounded by two nodes: the start (origin) node and the end (terminal) node. An edge has a coordinate string that describes the spatial representation of the edge. An edge may be a line string or an arc. An edge that lies between two faces has references to both of them. An edge may not cross itself ("figure 8") or any other edge.

A face, represented by a polygon, has a reference to edge lists of its outer perimeter as well as any holes or islands.

Persistent topology model elements are represented by standard element types:

• Nodes are point elements
• Edges are linear elements
• Faces are text elements with X attributes denoting boundary and direction

Persistent topology also has a binary "change tracker" stream containing cumulative topology transactions to facilitate posting into an Oracle Spatial topology.

At the current time, Bentley Map’s persistent topology model does not implement Oracle’s Topology Geometry Layer Hierarchy.