Network Simplification Group

Remove Short Dead Ends

This operation removes short dead ends in a network (typically a road network). Each time a dead end is eliminated, the remaining lines are reassessed, as eliminating one can affect the length of remaining dead ends. The shortest dead ends are removed first, unless two short dead ends meet at a junction. In this case, if one is more aligned with the road feeding the traffic into the junction, then it is preferred to the other. If however, none are reasonably aligned (like a T junction), then both are removed.

The following parameters are used:

• Parameter 1 (Object): The starting road.
• Parameter 2 (Double): The minimum length for a dead end to remain on the map.
• Parameter 3 (Double): Angle in degrees. All short dead ends deviating from the feeding road by more than this angle will be removed.
• Parameter 4 (Double): Distance along the line from the junction node where the second point will be taken to compute the angle (the first one is the junction node).
• Parameter 5 (String): Pipe separated list of class names. All features of these classes and their subclasses will be taken into account (considered part of the network).

The figure below shows an example where only the shortest dead end connected to the circled node was shorter than the minimum dead end length. It has therefore been removed in the result on the right-hand side.

Shortest dead end removed

In the next figure, the minimum length was increased so that both dead ends are shorter than the minimum. In this instance, the longer dead end is first to be removed because the angle of the short one is better aligned with the road feeding into the junction. Now that the longest dead end is removed, no further elimination is done.

Note: If both angle deviations had been higher than the one provided in parameter 3, both dead ends would have been removed and then the feeding road would have been removed as well, as it would be too short to remain alone.

An action is available for using this built-in operation on ROAD_TGT features, it is called "Remove Short Dead Ends" and is located under the "1Generalise Algorithms > Road folder".