how to get the edges of a contour ?

[Edi]

 I have a contour extracted from a 2D image with vtkContourFilter

 I would like to plot this contour as a polygon. If I do this directly with the output of  a filter, I get rather a mesh. How can I get only the external lines of this mesh ? Tried with ExtractEdges and FeatureEdges  but didn't succeed. Is there another way to do this ?

 Can I have the points of this external lines arranged in a clockwise order ?

 Thank you .


-----------------------------------------------------------------------------
This is the private VTK discussion list.  Please keep messages on-topic.
Check the FAQ at: <http://www.automatrix.com/cgi-bin/vtkfaq>
To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
<majordomo at gsao.med.ge.com>.  For help, send message body containing
"info vtkusers" to the same address.     Live long and prosper.
-----------------------------------------------------------------------------