[mkgmap-dev] shapes with holes

Tue Jan 29 19:55:37 GMT 2013

WanMil wrote
> I think it is not a good idea to focus on the 250 nodes limit. This 
> creates an implicit rule about the further processing after the 
> multipolygon has been calculated. And that will fail at some time in 
> future. (e.g. the java Area object is also used in the AreaClipper)
> 
> Without changing the splitting with the java Area object you might also 
> change the cutting procedure a little bit. Instead of completely 
> surrounding the inner polygons you might create singular polygons 
> without holes by partly surrounding the inner polygons. The algorithm 
> should not too complex if you have the information about the shortest 
> distances. I have implemented a similar algorithm a long time ago when I 
> tried a similar approach. But I abandoned because the calculations of 
> the shortest distances took much too long (I used a visibility graph 
> calculated by an external library).
> 
> This change makes it possible to keep the java Area calculations until 
> we find a good replacement.

I wanted to implement that, but I did not find an efficient way to calculate 
equally sized areas. If I just cut somewhere it is likely to have again
small
stripes. That's why I think that we should not use java Area for this, but 
I agree that a replacement isn't hard to find.
Looks so easy and is so complicated ;-)

Gerd
Gerd

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