[mkgmap-dev] Multipolygon problem

Sat Jan 8 09:59:58 GMT 2011

On 08/01/2011 13:02, Torsten Leistikow wrote:
> Moin,
>
> I think the problem is not the multipolygon, but that some of the outer ways are
> tagged with surface=sand. These tags are not considered for the multipolygon,
> but for these ways mkgmap creates single surface=sand polygons.
>
> But if you change your polygon style from
>
> surface=sand [0x1b resolution 20]
>
> to
>
> surface=sand&  natural!=coastline [0x1b resolution 20]
>
> this shouldn't happen any more.
>
> Just for a try: What happens, if you remove the surface=sand lines from your
> polygon styles completely?
>
> And one other thing: There was once a patch, which limited the polygon creation
> to closed ways. Does anybody know, what happened to this patch? I really liked it.
>
> Gruss
> Torsten
Hi Torsten,

You may be right - it might just be that the polygon rule makes mkgmap 
create a surface=sand polygon for coastline ways tagged with 
surface=sand.  Unfortunately it is legitimate to tag a way as 
surface=sand so I cannot correct the OSM data.  I need some way of 
telling mkgmap not to create a surface=sand polygon when it is 
associated with a coastline.

Unfortunately
surface=sand&  natural!=coastline [0x1b resolution 20]
does not solve the problem.

I think this may be because the natural=coastline tag is being removed 
during the --generate-sea processing, so it is no longer there when the 
polygon code starts.

The only way I can currently solve it is to remove the surface=sand rule 
completely, which I don't want to have to do.

Charlie