simplify method
Implementation
List<Coordinate> simplify()
{
usePt = List.filled(pts.length, true);
_simplifySection(0, pts.length - 1);
CoordinateList coordList = new CoordinateList();
for (int i = 0; i < pts.length; i++) {
if (usePt[i])
coordList.add(Coordinate(pts[i].x,pts[i].y));
}
return coordList.toCoordinateArray();
}