A Curve is a one-dimensional geometry,
          usually represented by a sequence of points. Particular
          subclasses of Curve define the type of
          interpolation between points. Curve is a
          noninstantiable class.
        
          Curve
          Properties
- A - Curvehas the coordinates of its points.
- A - Curveis defined as a one-dimensional geometry.
- A - Curveis simple if it does not pass through the same point twice, with the exception that a curve can still be simple if the start and end points are the same.
- A - Curveis closed if its start point is equal to its endpoint.
- The boundary of a closed - Curveis empty.
- The boundary of a nonclosed - Curveconsists of its two endpoints.
- A - Curvethat is simple and closed is a- LinearRing.