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Computes topology on input point, line, and/or area features.

This transformer is typically used to determine topological relationships to aid in decision making in later transformers (for example, the FeatureColorSetter).

This transformer does not assume that all input data is clean and noded properly unless Assume Clean Data is set to Yes. It takes any data and constructs the resulting topology after computing any intersections that are present in the input data.

Input Ports

Output Ports

The TopologyBuilder outputs the significant Nodes and Edges with attributes describing their topological relationships. Faces are output with information about the Edges that form them.

Note: Unlike most transformers, you cannot name these attributes.

Output Ports Output Feature Properties


All topologically significant nodes are output. Attributes may include _node_number, _node_angle{}.fme_arc_id, _node_angle{}.fme_arc_angle.


All topologically significant lines (edges) are output. Attributes may include _edge_id, _right_face, _left_face, _right_edge, _left_edge, _from_node, _to_node, _faces.


The polygonal (face) entities constructed are output here. These have a list of the edges which make up the face along with the actual geometry, and a list of the adjacent polygons. Attributes may include _creation_instance, _stop, _overlaps, _face_id, _faces, _perimeter, _area, or _edges.


This is the polygon that represents everything not covered by any of the input polygons. This feature consists of a list of the defining edge identifiers that make it up but does not have any associated geometry. Attributes may include _face_id, _perimeter, _area, _edges.

<Rejected> Features without point, text, curve or area geometries will be output through this port.





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.

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Geometric Operators


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Tags Keywords: connectivity hub Topologizer