Table 6.67 — DRM_Ellipse

Property

Description

Class
  • <DRM Ellipse>

Superclass

Subclass
  • None.

Definition

An instance E of this DRM class specifies a closed plane curve such that for each point P on the curve, the sum of P’s distances from two fixed points (called the foci of E) is a constant. The <DRM Location> component of E specifies the centre of the instance E.

The line passing through the foci of E is termed the major axis of E. The direction of the major axis of E is specified by the component <DRM Reference Vector> of E with vector_type = MAJOR_AXIS.

The line passing through the centre of E and perpendicular to the major axis of E is termed the minor axis of E. The direction of the minor axis of E is specified by the component <DRM Reference Vector> of E with vector_type = MINOR_AXIS.

The major_axis_length field is specified in metres.

The minor_axis_length field is specified in metres.

Clarifications

1 This corresponds to the centre of the given <DRM Ellipse> instance.

2 A <DRM Primitive Geometry> instance contains a <DRM Union Of Primitive Geometry> instance as a component only when that <DRM Primitive Geometry> instance can be decomposed into nested <DRM Primitive Geometry> instances, as (for example) a <DRM Polygon> instance can be decomposed into subfaces.

3 This is the location of the centre of the given <DRM Ellipse> instance.

4 For a given instance E of <DRM Ellipse>, one <DRM Reference Vector> component shall have vector_type = MAJOR_AXIS, the other shall have vector_type = MINOR_AXIS, and the two shall be mutually perpendicular.

Class diagram

Figure 6.78 — DRM_Ellipse

Inherited field elements

Field name

Range

Field data type

None

    

Field elements

Field name

Range

Field data type

major_axis_length

> 0,0...

Long_Float

minor_axis_length

> 0,0...

Long_Float

Associated to (one-way) (inherited)
  • None.

Associated to (one-way)
  • None.

Associated by (one-way) (inherited)
  • None.

Associated by (one-way)
  • None.

Associated with (two-way) (inherited)
  • None.

Associated with (two-way)

Composed of (two-way) (inherited)

Composed of (two-way)

Composed of (two-way metadata) (inherited)

Composed of (two-way metadata)
  • None.

Component of (two-way) (inherited)

Component of (two-way)
  • None.

Constraints

Example(s)

  • The physical extent of certain underwater acoustic phenomena are best described by oval surface geometries in some cases, and by <DRM Volume Object> instances in others.