[mkgmap-dev] Multipolygons and basic question on polygons with holes

Fri Jan 1 13:30:23 GMT 2010

On 01/01/10 13:15, Christian Gawron wrote:
> I still have the feeling that the cause of the problems with
> multipolygons may be due to the representation of "polygons with holes"
> in the img file.
> If I'm not mistaken, the multipolygon code connects the inner and outer
> polylines forming the multipolygon which either leads to spurious lines
> ("triangles", see sea polygons in mp-mode) or to vanishing inner polylines.

Yes that is what it does.

> Is this really the correct representation of "polygons with holes" in
> the img file?

I've no idea, I've been wondering too.  It could be that the way Mark is 
doing the sea/island polygons is the right way, except that if I'm not 
mistaken his method only works with a TYP file, whereas it is clearly 
possible to do this without since the MetroEurope maps don't have a typ 
tile.

I am going to look into some examples, if not today then tomorrow.

: There is also still a problem with the rendering of polygons with
> holes in the polish format. The attached mp-file is displayed correctly

Yes that case is just not implemented as far as I know.

Happy 2010 to everybody.

..Steve