I have put in the Beta Testing section of www.paris-pc-gis.com a first version of Split_Pgon that splits a one-polygon region with a one-section polyline. It may not be a unique tool for doing that, but in the process of writing it, I found that this kind of operation raises some very interesting topological issues. The beta testing that I invite you to undertake could be as well a source of reflections on these issues. The topological questions I have encountered are complementary. 1 - the object that would be obtained by merging the two "new halves" is not identical to the original one. That stems from the possible addition of a node in two different "sides" of the original region. The new node (intersection of polyline with polygon) does not fall always exactly on the segment. 2 - The modifications made (new nodes) must be replicated in regions adjacent to that "sides" to avoid creating a local topological distorsion (missing common node, gap or overlap) As a resut of the non-linearity of the added nodes and of the adjustments required by the second question, I have been able to observe small variations in region areas in some cases. I would love to hear your comments in that domain. Jacques Paris e-mail [EMAIL PROTECTED] MapInfo/MapBasic support http://www.paris-pc-gis.com _______________________________________________________________________ List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MapInfo-L" in the message body.
