This code list is used to indicate which sort of curve may be approximated by a particular B-spline. The potential values are:<br/>-- polylineform: a connected sequence of line segments represented by a 1 degree B-spline (a line string).<br/>-- circularArc: an arc of a circle or a complete circle.<br/>-- ellipticArc: an arc of an ellipse or a complete ellipse.<br/>-- parabolicArc: an arc of a finite length of a parabola.<br/>-- hyperbolicArc: an arc of a finite length of one branch of a hyperbola.<br/>