Determines whether areas, surfaces, and solids are convex or concave. A polygon is simple when it is not self-intersecting and has a non-zero area. Simple polygons are convex if every internal angle is less than or equal to 180 degrees. All other polygons are considered concave.


This diagram shows both convex and concave examples.

Usage Notes

  • Lines and points are considered concave.
  • The test is limited by the precision of the geometry’s coordinates – be careful of “invisible” bends in lines, as shown here:


Input Ports

Output Ports

If the geometry of the feature is polygon-based (such as a polygon, a donut, or a box) all of the geometry’s composing polygons are tested for convexity. Based on the results of this testing, the appropriate output port is determined.


There are no parameters for this transformer.

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.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the ConvexityFilter on the FME Community.

Keywords: convex concave "polygon based" "internal angle"