[mkgmap-dev] Duo Tagged polygon.

Fri Jan 29 15:28:05 GMT 2010

Hello

> What I was suggesting is that when mkgmap finds a line it looks in the
> line style&  no other,&  when it finds a polygon it looks in polygon&
> no other.  There would be no order or priority, mkgmap would look

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.

Regards,

..Steve