[mkgmap-dev] Multipolygons

Tue Aug 11 07:11:04 BST 2009

Steve Ratcliffe wrote:
> Hi
>
> I am going to merge all the multipolygon fixes.
> Including, if appropriate, the sea polygon changes.
>
> In addition to the patches sent to the list I also
> have permission to use the attached patch from Olaf Kähler
> which he describes as follows:
>
>   
>> I guess, mkgmap has a bug with "vanishing islands" in case of
>> multipolygons. The major problem seems to be, that in the polygon
>> splitting process (PolygonSplitterBase.java), the Java awt methods mess
>> around with the inner polygons, that were previously merged into the
>> outer polygons. I included a patch, that somewhat works, but still seems
>> to have a few issues. I've also included sample .osm files to explain
>> these issues:
>>     
>
> I'd appreciate it if anyone who understands the polygon issues
> takes a look at the patch.
>
> Also if you have an test cases which don't work with the current
> trunk but might be fixed by the outstanding patches let me know.
>
> ..Steve
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>
>
>   
I tested the three samples with build 1129 before and after applying the 
patch.

Before patch
--------------------------------
test1=lake with island
level0=fail (Island missing)
level1=okay
level2=okay

test2=lake with 2 islands
level0=fail (Islands missing)
level1=okay
level2=okay

test3=lake with island + small lake on island
level0=fail (Island & small lake missing)
level1=okay
level2=okay

After patch
--------------------------------
test1 all okay
test2 all okay
test3
level0=fail (Island & small lake missing)
level1=okay
level2=okay

So test 3 still fails, even after applying the patch, or did I do 
something wrong applying the patch?

The patch failed to apply properly for me, and I had to fix some errors 
by hand, so I could have made a mistake.

I will test my own samples next.

Thanks for the updates,

Garvan