protective decomposition

Function Description

Protective decomposition decomposes complex polygon objects with multi-level island-hole nested relationships into polygon objects with only one level of island-hole nesting. The difference between protective decomposition and decomposition is: if the polygon object to be decomposed has island-hole relationships, the result after protective decomposition will retain the simplest level of island-hole relationship polygon objects, while decomposition will decompose the island-hole relationship polygon objects together.

  • The protective decomposition function is applicable to line layers, polygon layers, and CAD layers.
  • Only complex objects or compounds can be decomposed; simple objects cannot be decomposed.
  • When decomposing a complex object (i.e., an object containing multiple sub-objects), the generated multiple single objects are all simple objects (except for island-hole objects); when decomposing a compound, multiple single objects are generated, and except for island-hole objects, if the generated single objects still contain compounds, they can continue to be decomposed until all are simple objects.

    As shown in the figure below, an island-hole object is combined with another object; after performing the protective decomposition operation on it, the new objects obtained are an island-hole object and a single object:

    Figure: Protective Decomposition of Complex Objects
  • In the attributes of the generated new objects, the field SmUserID and non-system fields inherit the corresponding information from the source object; other system fields are assigned by the system.

Function Entry

  • Edit Data Tab -> Feature Editing Group -> General editing -> Group and Ungroup -> Protective Decomposition

Operation Steps

  1. In the editable state of the layer, select one or more complex objects or compounds.
  2. In the Edit Data tab, under the General editing drop-down menu, click the Protective Decomposition button in the Group and Ungroup group to perform the protective decomposition operation.