[Talk-us] Can-Amera border, states and provinces.

[Lennard]

Minh Nguyen wrote:

> Someone on either the dev or U.S. list explained that borders with fewer 
> twists and turns will show up lighter when zoomed out. That is, Mapnik 
> doesn't perform any smoothing on country boundaries yet.

If there are many twists and turns, that could indeed make the border 
appear darker. The main reason, however, is that currently mapnik 
renders every way and every relation tagged with boundary=administrative 
and admin_level=*, and renders all of them on top of each other.

So where a national (or sub-national) border is both tagged on the way, 
and a member of the two respective national boundary relations, it's 
drawn three times. If you zoom in to where provinces/states come into 
play, and later even municipalities, this issue gets progressively worse.

> Also, changeset 17070 [1] sounds like an attempt to address this issue.
> 
> [1] http://trac.osm.org/changeset/17070

This is currently rendering. I've forced several lowzoom tiles to be 
rerendered. If you notice any state or province boundary still missing, 
that tile might not have rerendered.

Canada looks good, so does Australia, for that matter. admin_level=4 
renders from z4. z4 shows ref=* for states, z5-z8 show name=*.

The USA however, not so good. Specifically, the place=state nodes are 
all* placed in the extreme southwest corners of the states. None of them 
have been tagged with ref=*. I noticed that when developing that 
changeset, but figured it would sort itself out quickly enough once it 
started rendering.

* CA and WA have additional place=state nodes created, which are placed 
centrally in the state, and have ref=* applied.

So, have a look, see what you think, and start editing those state 
nodes! :-)

-- 
Lennard