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Repairs area topologies by resolving gaps and overlaps between adjacent areas. An overlap occurs where two or more areas intersect each other, creating an region covered by multiple areas. A gap occurs where two or more areas fail to meet at a boundary.

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How does it work?

The AreaGapAndOverlapCleaner cleans gaps and overlaps by constructing a 2D planar partition from the input areas using the specified tolerance.


Usage Notes

  • Requires valid area geometries. For example, self-intersecting, or degenerate areas will not be properly repaired.
  • All overlaps will be cleaned, even if they are larger than the tolerance.
  • The AreaGapAndOverlapCleaner resolves gaps and overlaps between adjacent areas. If a single area is input, it will be output unchanged.
  • The AreaGapAndOverlapCleaner may create spikes when merging large overlaps to adjacent areas. However, spikes smaller than the tolerance will never be created. If these spikes are not desired, try increasing the tolerance.
  • Donut holes, if not filled by another area, are gaps in the 2D planar partition.


Input Ports

Output Ports


Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.


Processing Behavior


Feature Holding


FME Licensing Level FME Professional Edition and above
Aliases SliverRemover

Data Quality


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Examples may contain information licensed under the Open Government Licence – Vancouver