[mkgmap-dev] Multipolygons code rewritten (1st try)

Tue Dec 29 21:11:24 GMT 2009

Hi,

I have rewritten the MultiPoloygonRelation class regarding the algorithm 
described in 
http://wiki.openstreetmap.org/wiki/Relation:multipolygon/Algorithm.

This is a first (very early and not very well tested) implementation of 
this algorithm. I don't have time to go on with it within the next days. 
Multipolygons are a big discussion in the mailing list at the moment so 
maybe someone likes to review the code and gives some helpful comments 
on it. (Any comment is very welcome!!)

These are the open points:
* Tagged inner polygons are not considered yet! This a big open point 
which must be implemented next. (Some comments point to the place where 
to do this)
* The code currently does not remove any inner or outer polygon segment. 
This must be changed in future. But at the moment I have no solution how 
to decide which segment should be removed and which segment must remain 
for map generation. (To be honest I did not think about it for long ;-)
* The inner and outer tags in the polygon are not used at the moment. 
This must also be changed.
* The code is completely unoptimized. It's just an early study if this 
can improve the multipolygon code. I am happy about any improvements!
* The old insertPoints method does not consider the direction of the 
polygons. This can result in self intersecting polygons. I don't know if 
that matters but it can easily be improved. I am happy if someone can 
explain me if that matters than I can implement a fix (hopefully :-).
* I don't know if my synthetic ids are generated well. I think there 
should be one synthetic generator for whole mkgmap?

Have a happy new year (with the multipolygons case fixed :-)))
WanMil
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