Creates an ILcdValuedPolygon from separate arrays of x- and y-coordinates
where only the first aNumberOfPoints are taken into account.
The edge of a polygon indicates a contour line of equal height. The orientation of the returned
polygon should be interpreted as follows:
CLOCKWISE: The area on just on the exterior of the polygon has a higher value than the interior.
COUNTER-CLOCKWISE: The area just on the exterior of the polygon has a lower value than the interior.
Note that this orientation only says something about the immediate area surrounding the contour line, and not the
entire area enclosed by the contour. For instance, it is possible to have a counter-clockwise oriented
contour that contains other contours in its interior with lower values than itself.