ISO/IEC 18023-1:200x(E) — Table 6.62 DRM

Table 6.62 — DRM_Ellipse

Property

Description

Class

<DRM Ellipse>

Superclass

<DRM Surface Geometry>

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 <DRM Reference Vector> component 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 <DRM Reference Vector> component 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.

Class diagram

Figure 6.76 — 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

Default field values

Default field values for DRM_Ellipse

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)

zero or one <DRM Geometry Node> instance¹

Composed of (two-way) (inherited)

zero or one <DRM Classification Data> instance
zero or more {ordered} <DRM Property Set Index> instances
zero or more <DRM Property Table> instances
zero or more <DRM Property Table Reference> instances
zero or more <DRM Property Value> instances
zero or more <DRM Colour> instances
zero or more {ordered} <DRM Image Mapping Function> instances
zero or one <DRM Light Rendering Properties> instance
zero or one <DRM Presentation Domain> instance
zero or one <DRM Rendering Priority Level> instance
zero or one <DRM Rendering Properties> instance
zero or more <DRM Tack Point> instances
zero or one <DRM Union Of Primitive Geometry> instance²

Composed of (two-way)

one <DRM Location> instance³
exactly two <DRM Reference Vector> instances⁴

Composed of (two-way metadata) (inherited)

zero or one <DRM Time Constraints Data> instance

Composed of (two-way metadata)

None.

Component of (two-way) (inherited)

zero or more <DRM Union Of Primitive Geometry> instances

Component of (two-way)

None.

Constraints

Clarifications

¹The <DRM Geometry Node> instance corresponds to the centre of the <DRM Ellipse> instance.

²A <DRM Primitive Geometry> instance P has a <DRM Union Of Primitive Geometry> component only when P can be decomposed into nested <DRM Primitive Geometry> instances.

EXAMPLE A <DRM Polygon> instance can be decomposed into multiple <DRM Polygon> instances representing subfaces.

³The <DRM Location> component is the location of the centre of the <DRM Ellipse> instance.

⁴For a given <DRM Ellipse> instance, 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.

Example(s)

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