MapInfo SQL for skeleton of polygon

Question

I would like to know if anyone has found a way to make an SQL query in MapInfo (I use 11.5) that can calculate the skeleton of a polygon that has multiple intersections AND generate the polyline for it, or any combination of steps to follow to get a resulting centerline. I work with underground utilities and I receive data as a prebuffered polygon which is based on the centerline buffered out 300 to 500 ft. I want the reverse of buffering a line into a polygon basically. I have reviewed http://www.cgal.org/Manual/3.2/doc_html/cgal_manual/Straight_skeleton_2/Chapter_main.html but I dont know how I can get that into a SQL statement that Mapinfo can do anything with.

Answer 1

If you want to use it in MapInfo SQL, you need to create a MapBasic application, write a function that does what you want, and then use it in SQL query in the same application. MapInfo does not allow using custom functions in its dialog boxes.

But in this case you need to rewrite CGAL algorithm in your own MapBasic function. Or compile a DLL with necessary function from CGAL source code, and then declare and use that DLL function in your MapBasic application.