[OSM-talk] place=island rendering

[Andy Allan]

On Thu, Mar 12, 2009 at 11:31 AM, Ted Mielczarek <ted at mielczarek.org> wrote:
> I've noticed that there's a GNIS import going on in the USA recently, and
> one of the types of POIs being imported are islands, which are tagged
> place=island. Of course, the GNIS database contains some very tiny islands,
> but Mapnik renders place=island up to z10. For example:
> http://www.openstreetmap.org/?lat=40.69&lon=-75.353&zoom=10&layers=B000FTFT
>
> Allentown is a city with a population of 100,000. Eves Island appears to be
> about 20 feet long, yet the label for it is nearly the size of Allentown. :)
> Someone on IRC suggested that place=islet might be a more correct tagging
> for these, and the map features page for place=island seems to agree:
> http://wiki.openstreetmap.org/wiki/Tag:place%3Disland
> "I am mainly thinking of small coastal or river islands which may have a
> small settlement or a farm"--this indicates that tiny little patches of land
> weren't the original target of this tag.
>
> Thoughts?

Interesting issue. The techy in me thinks that tagging the island (tag
the way) rather than a point may help, since that allows data
consumers (e.g. renderers) to calculate the size of the island (and
even, perhaps in future, the longest diagonal to write the name at an
angle). Defaulting to putting the name in the middle of the polygon is
easy and done already with buildings. We have a similar area-based
thing with way_area in mapnik rendering rules already.

But that might be overcomplicating things, I'm not sure. It would
allow renderers to bring in islands based on how big they were,
whereas making a distinction between island/islet might still have
problems.

Cheers,
Andy