init method
void
init()
Implementation
void init() {
List<Coordinate> pts = parentLine!.getCoordinates();
segs = List.empty(growable: true);
for (int i = 0; i < pts.length - 1; i++) {
TaggedLineSegment seg =
new TaggedLineSegment(pts[i], pts[i + 1], parentLine, i);
segs.add(seg);
}
}