Timeline for How to synchronize segments in polylines?

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Dec 17, 2015 at 10:26	comment	added	Doc Brown		... and yes,as I wrote in my initlal comment above, the offset algo knows which segments it maps from polygon 1 to polygon 2, so if you have access to that code, implement it there, makes things a hell lot easier than post-mortem reconstruction.
Dec 17, 2015 at 10:22	comment	added	Doc Brown		@greenoldman: the algorithm above does not "search the second polygon", it expects you know the coordinates of the vertices of the second polygon already, and it describes how to find the associations between vertices and segments of the two polygons. That is exactly what you asked for in your comment above. Now you bring the precision problem on the table, not one word before of that :-((( You should really edit your question and write a more precise description. FWIW, the precision problem can typically be solved by using some tolerance values.
Dec 17, 2015 at 10:06	comment	added	greenoldman		Thank you, but the problem is not here "search the second polygon" -- I don't have to search, it is the next segment or not. The problem is, those segments could be small, and testing for being parallel in computer world with finite precision could lead to false detections (for both outcomes). How to overcome this, I don't know (yet). The more I think, the more I am convinced that synchronization has to be part of offset algorithm, meaning DIY from the beginning :-).
Dec 17, 2015 at 8:56	history	answered	Doc Brown	CC BY-SA 3.0