Rule Name: Connected Edge Restrictions

Definition

  1. A Feature Node has a Connected Feature Edge component if and only if that Feature Node is the endpoint of some Feature Edge(s).

  2. For each Feature Edge in the collection of Feature Edges associated with a Connected Feature Edge component of a Feature Node, that same Feature Node must be associated with either the Feature Edge Starting Node, or the Feature Edge Ending Node component Feature Edge, and vice versa.

  3. A Geometry Node has a Connected Geometry Edge component if and only if that Geometry Node is the endpoint of some Geometry Edge(s).

  4. For each Geometry Edge in the collection of Geometry Edges associated with a Connected Geometry Edge component of a Geometry Node, that same Geometry Node must be associated with either the Geometry Edge Starting Node, or the Geometry Edge Ending Node component Geometry Edge, and vice versa.

Rationale

Connected Feature Edge is the one-directional topological relationship between a Feature Node and the ordered set of ordered collections of Feature Edges that are connected to it; if there are no Feature Edges connected to the Feature Node, by definition there should not be a Connected Feature Edge on that node.

Connected Geometry Edge is the one-directional topological relationship between a Geometry Node and the ordered set of ordered collections of Geometry Edges that are connected to it; if there are no Geometry Edges connected to the Geometry Node, by definition there should not be a Connected Geometry Edge on that node.

Example

  1. Consider a Feature Node X that is the endpoint of Feature Edge A. X must have a Connected Feature Edge in order to be valid.

  2. Consider a Geometry Node X that is the endpoint of Geometry Edge A. X must have a Connected Geometry Edge in order to be valid.

  3. Consider Feature Node Y that is not the endpoint of any Feature Edge. If Y is mistakenly created with a Connected Feature Edge, then Y is invalid, since the Connected Feature Edge implies that Y does belong to some Feature Edge.

  4. Consider Geometry Node Y that is not the endpoint of any Geometry Edge. If Y is mistakenly created with a Connected Geometry Edge, then Y is invalid, since the Connected Geometry Edge implies that Y does belong to some Geometry Edge.

FAQs

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