[mkgmap-dev] Duo Tagged polygon.

Fri Jan 29 16:12:28 GMT 2010

Steve Ratcliffe wrote:
> Hello
> This is not so easy, because you don't know if something is a line or
> a polygon until you look it up.  Having the first point equal to the
> last is not decisive because sometimes lines go in circles (eg.
> roundabouts, fence around a field) and sometimes polygons are split
> into pieces.
>
> Sometimes whether something is to be a line or a polygon depends on
> the map.  So for instance county boundaries are often represented by a
> multi-polygon in OSM but we represent boundaries by a line on the map.
> If you were creating a political map though you might want to use
> areas instead.
>
> Thats not to say there are no improvements possible (for instance the
> multipolygon relation did not exist when the current scheme was
> designed, but might be a hint that something should be a polygon -
> although in the cases when it is used as a boundary this is not valid
> for us), but keep in mind that the style is deciding the structure of
> the map and not just how it looks.
>   
Thanks for reply. I understand the problem now.

Cheers
Dave F.