CenterLineReplacer

From Fmepedia

CenterLineReplacer is a Workbench Transformer. Replaces an area feature with its centerline. This works best with long, narrow areas.

If Medial Axis or Straight Skeleton is selected, then the geometry of an area feature is replaced by its "angular bisector network"; in the case of Medial Axis, all edges which share a vertex with the original area are removed. See the @ConvertToLine section in the FME Functions, Factories, and Transformers manual for details.

In either of these modes, the algorithm may take a long time to run on large input features. The efficiency is given as O(n*m), where n is the total number of vertices, and m is the number of "reflex vertices" - vertices causing the polygon to be non-convex.

In Classic mode, the geometry of an area feature is replaced with a line that threads through the center of the feature. Only works well with long, thin features. In this mode, the line tolerance parameter is used to point thin the resulting line, by generalizing it. It is measured in ground units. It may either be entered as a number, or can be taken from the value of a feature attribute by selecting the attribute name from the pull down list.

Because Z coordinates are not considered in either center line algorithm, all features passing through this transformer are forced to 2D.

NOTE: The algorithm used to calculate the angular bisector network for the Medial Axis or Straight Skeleton mode was designed by Petr Felkel and Stepan Obdrzalek and is provided as-is, with no warranties. A reference to the relevant paper can be found in the @ConvertToLine section of the FME Functions and Factories Manual.