Median line
This function creates a "median" polyline, that is to say:
for each input vertex, other polylines are cut into segments which have the same length ratio
then the gravity center is computed for each set of vertices
finally, gravity centers are joined so as to create the median polyline
Requirements
Select several polylines and launch the command.
Make sure that the selected polylines have the same direction.
Technical information
Fig. Perspective view: green polylines: inputs, purple points: new vertices, red polyline: median polyline