[mkgmap-dev] type=multipolygon relations

Sun Jan 19 18:00:31 GMT 2014

Hi Gerd,

from my point of view it's ok to remove duplicate ways from mps.

Anyhow I didn't find a sentence on 
http://wiki.openstreetmap.org/wiki/Multipolygon that this is disallowed.
I can think of two touching inner polygons:

11111111111111111111111111
1                        1
1      22234444          1
1      2  3   4          1
1      2  3   4          1
1      22234444          1
1                        1
11111111111111111111111111

MP: tags natural=forest
Way 1: role=outer
Way 2: role=inner, natrual=scrub
Way 3: role=inner, natrual=scrub
Way 4: role=inner, natrual=scrub

It seems to be allowed to have 2+3 and 3+4 as inner polygons in the mp. 
In this case way 3 would have to be added twice to the mp.

I think we can ignore such a case but we should keep it in mind.

WanMil

> HI Marko,
>
> I agree that this should be flagged.
> I tried it with the data for Netherlands and I see no other problems
> besides the one
> in my example, so it doesn't see to happen that often.
>
> Attached small patch changes mkgmap so that repeated
> elements are ignored (the first one is used, ignoring differences in roles)
>
> If I hear no complains I will commit it next weekend.
>
> Gerd
>
>  > Date: Sun, 19 Jan 2014 00:16:15 +0200
>  > From: marko.makela at iki.fi
>  > To: mkgmap-dev at lists.mkgmap.org.uk
>  > Subject: Re: [mkgmap-dev] type=multipolygon relations
>  >
>  > On Sat, Jan 18, 2014 at 10:58:58PM +0100, Minko wrote:
>  > >Good luck for correcting them, there are tons of those faulty mp's all
>  > >over the place in NL's ;-)
>  > >I wouldnt spend too much time for this, better ignore it.
>  >
>  > I have found the existing multipolygon and coastline warnings very
>  > useful. The check for duplicate member ID in a multipolygon relation is
>  > cheap and has to be done anyway. There is really no good reason not to
>  > warn about them.
>  >
>  > By default, the log output is not enabled. You have to specify
>  > -Dlog.config=logging.properties in order to enable the diagnostic. Even
>  > after doing so, you could filter out these particular messages either by
>  > grep -vf or by configuring the logging.properties file appropriately.
>  >
>  > Marko
>  > _______________________________________________
>  > mkgmap-dev mailing list
>  > mkgmap-dev at lists.mkgmap.org.uk
>  > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>
>
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>