Feature Description

Protective Decomposition breaks down complex polygon objects with multi-level island-hole nested relationships into simpler polygon objects containing only single-level island-hole relationships. The key difference from regular decomposition is: When processing polygon objects with island-hole relationships, Protective Decomposition preserves the simplest single-layer island-hole structure, whereas regular decomposition would split both the main polygon and its holes completely.

• The Protective Decomposition function applies to line layers, polygon layers, and CAD layers.
• Only complex objects or compound objects can be decomposed; simple objects cannot be processed.
• Decomposing complex objects (objects containing multiple sub-objects) generates multiple simple objects (except island-hole objects). Decomposing compound objects produces multiple single objects. If any resulting objects still contain compound elements (excluding island-hole objects), they can be further decomposed until all become simple objects.

  The following diagram shows an island-hole object combined with another object. After performing Protective Decomposition, the resulting objects consist of one island-hole object and one single object:

  Figure: Protective Decomposition of Complex Objects

• In the attribute tables of resulting objects: The SmUserID field and non-system fields inherit information from source objects; other system fields are assigned by the system.

Feature Entry

• Features Tab->Feature Editing Group->Protective Decomposition.

Steps

1. With the layer editable, select one or more complex objects or compound objects.
2. In the Gallery control of the Feature Editing group on the Features tab, click the Protective Decomposition button to execute the operation.