@Override
    public String toString() {
      return "Edge{" + from.id + "->" + to.id + (main ? "" : "(R)") + ": [" + coordinates.getFirst() + ".." +
        coordinates.getLast() + "], length=" + length + '}';
    }
Processes the added geometries and returns the merged linestrings.
<p>
Can be called more than once.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/LoopLineMerger.java