The SEDRIS Data Representation Model
APPENDIX A - Classes
Feature Edge

Class Name: Feature Edge

Superclass - <Feature Topology>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class is a one-dimensional <Feature Topology> instance consisting of an ordered collection of <Location> instances connecting one <Feature Node> instance to another <Feature Node> instance. The orientation of a <Feature Edge> instance is defined by the order of its <Location> components, taken in conjunction with its starting <Feature Node> instance and ending <Feature Node> instance.

A <Feature Edge> instance is used to represent the location of a segment of one or more <Linear Feature> instances, and/or a boundary of one or more <Feature Face> instances.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. A <Linear Feature> instance representing the centreline of a road is defined by one or more <Feature Edge> instances.

  2. The border of a forested area is defined by a collection of one or more <Feature Edge> instances.

FAQs

When are <Feature Edge> instances required?

<Feature Edge> instances are required whenever either <Linear Feature> or <Feature Face> instances are present.

Does the sequence of <Location> instances that make up a <Feature Edge> instance include the endpoints?

No. The endpoints of a <Feature Edge> instance are defined by its ordered <Feature Node> associates.

Are there any geometric constraints on the sequence of <Location> instances that make up a <Feature Edge> instance?

Yes; see the constraints on this class for details.

How are <Feature Edge> instances affected by the feature topology level?

At feature topology level 2 or higher, no <Feature Edge> instance may intersect with or overlap another <Feature Edge> instance. At feature topology level 3, each <Feature Edge> instance forms part of the boundaries of exactly two <Feature Face> instances.

Constraints

Associated to (one-way)

Associated by (one-way)

Associated with (two-way)

Composed of (two-way) (inherited)

Composed of (two-way)

Component of (two-way) (inherited)

Inherited Field Elements

This class has no inherited field elements.

Notes

Associated to Notes


Feature_Face

These are the <Feature Face> instances (if any) that are bordered by the <Feature Edge> instance, ordered counterclockwise when looking along the <Feature Edge> instance.

The converse of this relationship is that between <Feature Face Ring> instances and <Feature Edge> instances.

Associated from Notes


Feature_Face_Ring

This association specifies that the <Feature Face Ring> instance is bounded by the <Feature Edge> instance.

Associated with Notes


Feature_Node

This association specifies that the <Feature Edge> instance is bounded by these two <Feature Node> instances.

The first <Feature Node> instance is the starting node of the <Feature Edge> instance, while the second <Feature Node> instance is the ending node.


Feature_Volume

This association specifies that these <Feature Volume> instances contain the <Feature Edge> instance.


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