Class

• <DRM Edge Direction>

Superclass

• <DRM SEDRIS Abstract Base>

Subclass

• None.

Definition

An instance of this DRM class indicates, for the associated relationship, whether the target edge should be traversed forwards (from start node to end node) or backwards (in the opposite direction).

Class diagram

Figure 6.76 — DRM_Edge_Direction

Constraints

• Publishable Object

Example(s)

• A <DRM Linear Feature> instance representing a stream is associated with several <DRM Feature Edge> instances that define the path of the stream. The <DRM Edge Direction> associated with each <DRM Feature Edge> has forwards = TRUE if the <DRM Feature Edge> is oriented so that the stream flows in the direction from its starting node to its ending node, and FALSE if the stream flows in the opposite direction.

• Consider a <DRM Linear Feature> instance representing a one-way street. Its path is defined by a <DRM Feature Edge>, so that the <DRM Edge Direction> between the <DRM Linear Feature> and the <DRM Feature Edge> indicates whether the orientation of the <DRM Feature Edge> matches the permitted direction of travel along the one-way street.

• The external <DRM Feature Face Ring> of a regular <DRM Feature Face> consists of three <DRM Feature Edge> instances. In traversing the ring, the first <DRM Feature Edge> might be traversed from starting node to ending node, so that its <DRM Edge Direction> has forwards = TRUE If the next <DRM Feature Edge> was traversed from its ending node (which in this example is the same <DRM Feature Node> as the ending node of the previous <DRM Feature Edge>) to its starting node, its <DRM Edge Direction> would have forwards = FALSE (that is, backward).