The SEDRIS Data Representation Model
APPENDIX B - Constraints
Classification Data Constraint

Definition

  1. For a <Union Of Features> instance UF,
    1. If UF has a directly attached <Classification Data> component, UF's union_reason may not be SE_UNION_REASON_OTHER.
    2. If UF has an inherited <Classification Data> component, UF's union_reason may not be SE_UNION_REASON_OTHER.
    3. Otherwise, UF's union_reason is required to be SE_UNION_REASON_OTHER.
  2. For a <Union Of Geometry> instance UG,
    1. If UG has a directly attached <Classification Data> component, UG's union_reason may not be SE_UNION_REASON_OTHER.
    2. If UG has an inherited <Classification Data> component, UG's union_reason may not be SE_UNION_REASON_OTHER.
    3. Otherwise, UG's union_reason is required to be SE_UNION_REASON_OTHER.

Rationale

The only permitted cases are those where a <Classification Data> is present to indicate either the SE_UNION_REASON_CLASSIFIED_OBJECT or SE_UNION_REASON_COLLECTION_OF_CLASSIFIED_OBJECTS cases, or where no <Classification Data> is present and the union is there for some non-semantic/non-environmental-object related reason.

Example

  1. Consider a <Union Of Features> instance UF that is a component of a <Classification Related Features> instance. UF's union_reason cannot be SE_UNION_REASON_OTHER, because UF inherits the link object <Classification Data> of its branch.

  2. Consider a <Union Of Geometry Hierarchy> instance UGH with <union_reason> = SE_UNION_REASON_COLLECTION_OF_CLASSIFIED_OBJECTS, with a component <Union Of Primitive Geometry> instance UPG. UPG's union_reason cannot be SE_UNION_REASON_OTHER, because UPG inherits UGH's <Classification Data>.

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Last updated: July 16, 2004 Copyright © 2004 SEDRIS™