The image I've attached represents a road; the grey line is the top of an embankment and the red line represents the bottom of the embankment. I would like to find the difference in height between these lines at perpendicular points.
Hopefully I've explained this clearly. I would be grateful for any suggestions! :)
You should start with the road axis to get the perpendiculars, else create a Concave Hull of the 2 sides with HullAccumulator coupled with CenterLineReplacer.
Use a combination of 3 custom transformers from the FME Hub: LineDivider (Line Lenght), 2DVectorCalculator (Vector Direction = Normal Right, Vector Lenght = 1) and LineToIntersectionExtender (2DVectorCalculator output as Candidate and bottom embankment as Base) to get the perpendicular lines.
Drape the perpendiculars on the surface created by the embankments. Use LineOnLine and keep just the segment between gray and red, CoordinateExtractor (0 and -1 for start and end vertex) and you have the ZValue of both points.