Class Name: Feature Model

Superclass - SEDRIS Abstract Base

Definition

Primary Page in DRM Diagram:

• 2

Secondary Pages in DRM Diagram:

• 7
• 8
• 16

Example

1. A level of VITD data.

FAQs

Can Level 0 feature topology be represented in SEDRIS?

Yes. Although in VPF, for example, the mere presence of Connected Nodes implies Level 1 topology, this is not the case in SEDRIS. The SDRM requires Feature Nodes to exist to contain the endpoint coordinates of Feature Edges. Consequently, the presence of Feature Nodes means nothing by itself. If, within a single topological layer, any two different Feature Nodes have the same Location coordinates, the topology level is Level 0. If no two Feature Nodes have identical Location coordinates, the topology level is (at least) Level 1.

Which objects (and relationships) are required to exist at each feature topology level?

At Level 0, unless the data consists solely of isolated (i.e., entity) Feature Nodes, the following objects (and the relationships among them) are all required to exist:

• Feature Edge
• Feature Edge Starting Node
• Feature Edge Ending Node
• Feature Node
• Connected Feature Edge

All other types of feature topology objects and relationships MAY also exist at Level 0, but the requirements of Level 1 are NOT met.

At Level 1, no additional objects or relationships are required. However, each Feature Node must have a unique Location (i.e., two or more Feature Nodes cannot be colocated).

At Level 2, no additional objects or relationships are required. However, Feature Edges may not intersect or overlap one another, except where they meet at a common Feature Node.

At Level 3, the remaining objects and relationships are required to exist:

• Feature Face (Regular and Universal)
• Feature Face Ring (External and Internal)
• Bordered Feature Face
• Contained Feature Node
• Contained Within Feature Face

The set of Feature Faces must be exclusive and exhaustive, forming a complete surface (i.e., Feature Faces may not intersect or overlap one another, except where they meet at a common Feature Edge). Exactly two Feature Faces border each Feature Edge.

At Level 4, Location 3Ds are required, and there must be at least one case where more than two Feature Faces meet at a single Feature Edge.

Constraints

Associated by (one-way)

• optionally, some Feature Model Instances

Composed of (two-way)

• one Feature Hierarchy

Composed of (one-way metadata)

• optionally, an Access
• optionally, some Browse Graphics
• optionally, some Cross References
• optionally, a Data Quality
• optionally, a Keywords
• optionally, a Point of Contact

Component of (two-way)

• one Model

Field Elements