[mkgmap-dev] Explanation of the is_in function

Fri May 22 21:44:25 BST 2020

Hi Gerd

I think I understand what is going wrong. I'll do another patch
tomorrow.

Ticker

On Fri, 2020-05-22 at 13:36 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> the patched version still returns ON for a Coord which is not ON and
> thus doesn't work with my example.
> The result doesn't depend on the position of the last point of the
> way as long as it is builds a nearly or exactly straight line with
> two nodes of the shape.
> 
> Your algorithm returns true for each such point, even when it is 100m
> away from any shape vertex.
> See my new example where A,B and C build a straight line. Another
> node is very close to the edge but still returns  IN (OK)
> 
> Gerd
> 
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> Gesendet: Donnerstag, 21. Mai 2020 17:07
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] Explanation of the is_in function
> 
> Hi Gerd
> 
> Here is patch that prevents possible underflow when node is very
> close
> to an almost horizontal or vertical line and incorrect results when
> exactly on this line.
> 
> Ticker
> 
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev