The SEDRIS Data Representation Model
APPENDIX A - Classes
Feature Face Ring

Class Name: Feature Face Ring

Superclass - <SEDRIS Abstract Base>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies the one-directional topological relationship from a <Feature Face> instance to the ordered collection of one or more <Feature Edge> instances that define one of its boundaries (outer or inner).

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

This class appears on only one page of the DRM class diagram.

Example

  1. Consider an <Areal Feature> L representing an ECC_LAKE. The topology of L is represented by a regular <Feature Face>, the outer boundary of which is defined by 2 <Feature Edge> instances, one defining the north shore of the ECC_LAKE, the other defining the south shore.

    To indicate that these 2 <Feature Edge> instances define the outer boundary of the ECC_LAKE, they are components of an external <Feature Face Ring>, which is in turn a component of the <Feature Face> specifying the topology of L. The <Edge Direction> associated with each <Feature Edge> indicates its orientation with respect to the <Feature Face Ring>.

    Feature Face Ring, Example 1

FAQs

When are <Feature Face Ring> instances required?

All <Feature Face> instances are required to have at least one <Feature Face Ring> component, regardless of feature topology level. A <Feature Face> shall have an <Feature Face Ring>, which defines its outer boundary, and may have any number of <Feature Face Ring> components, which define inner boundaries (that is, "holes") within the <Feature Face>. A "universal" <Feature Face> has no external <Feature Face Ring>, but will have one or more internal <Feature Face Ring> components.

Can the same <Feature Edge> appear more than once in the collection of <Feature Edge> instances making up a <Feature Face Ring>?

Yes. A <Feature Edge> can appear up to twice in a <Feature Face Ring>, once with each orientation.

Constraints

Associated to (one-way)

Component of (two-way)

Inherited Field Elements

This class has no inherited field elements.
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Last updated: July 16, 2004 Copyright © 2004 SEDRIS™