[OSM-talk] Mapnik: strange prioritisation/appearance of place names

[Kærast]

On Mon, 23 Mar 2009 11:18:22 +0900
Woll Newall <woll at 2-islands.com> wrote:

> In the OSM Mapnik slippy map, the rendering of place names seems to
> be rather "random" at different zoom levels. Cities seem to appear
> and disappear as I zoom in, and 'large' cities don't appear but
> 'tiny' ones do.

There's always been problems with hierarchies of places, and I really
think it's about time we did something about it.  Particularly
towns/cities where we need some way of tagging a city's importance.
Two examples come to mind:

Istanbul, Turkey which according to Wikipedia is the fourth largest city
in the world.  Doesn't appear when zoomed out but Ankara, the
official capital does.

St Davids, Wales.  Which is the size of a village, is officially a
city, but has the importance of a town.  Whilst nearby Haverfordwest is
more important, being the main town in the county, but doesn't appear
because a city is considered more important.

But also other features such as rail lines and railway stations, peaks,
etc.

We need to keep the village/town/city tags because it is important to
know the official designation of a place, so what we need is a tag to
designate how important the place is and therefore what zoom levels it
shows on.  However, this would be tagging for the renderer and
therefore considered by most to be inherently bad.

-- 
Alice