[OSM-talk] National borders - mapnik

[Steve Chilton]

Logically, any border that is both a state and national border should be tagged at the highest level (in this case national, admin_level=2).
Similarly in UK any border that is both county and country should be tagged at highest level (country, admin_level=2).
That way all the country borders will show at designated zoom levels. When you move to a level that state (or whatever) comes in the country border will already be there (in its appropriate style) and the state borders will come in too, with their appropriate style.
Currently there is an /Else filter which picks up borders that have no admin_level set, but it necessarily doesn't come in till higher zooms, which appears to the case for your example below.
 
Cheers
STEVE
 
-----Original Message----- 
From: blodulv at gmail.com on behalf of Beau Gunderson 
Sent: Wed 5/28/2008 8:42 PM 
To: Steve Chilton 
Cc: talk at openstreetmap.org 
Subject: Re: [OSM-talk] National borders - mapnik



	The US national border with Canada is all tagged with admin_level=4, border_type=state, border=administrative... It also has the left/right countries (at least the bit I looked at in WA did).
	
	How should state borders that are also national borders be tagged?
	
	Does setting admin_level=2 fix the whole problem?
	
	As you can see, they're not currently visible at low zooms:
	
	   http://www.openstreetmap.org/?lat=48.83&lon=-118.46&zoom=7&layers=B00FF
	
	
	Beau
	
	
	On Wed, May 28, 2008 at 1:21 PM, Steve Chilton <S.L.Chilton at mdx.ac.uk> wrote:
	

		The latest mapnik stylesheet has the National borders moved from coming in at z10 to coming in at z7. Now zooms to z6 show the borders as thin blue lines taken from the shape files, and then switch to OSM data at z7 using a slightly thicker purple line.
		Not all borders show, for one of two reasons - either they are not digitised or are not tagged appropriately.
		So, it would be useful if folk have a look at their own country/area at z7.
		Does in show correctly?
		If not:
		1 - check whether it has been digitised. If not - is there a valid, non-copyrighted source for putting in the border alignment.
		2 - check whether it is tagged boundary=administrative, admin_level=2. If not - change the tagging to that so that it may show.
		
		As a reminder, admin boundaries should be tagged for the admin_level that they are (at the highest level). Country/national borders are always admin_level=2. Internal borders should be tagged according to the suggested schema for that particular country. Details are on the wiki at:
		http://wiki.openstreetmap.org/index.php/Key:boundary
		which also explains the accepted way to tag for the countries on either side of the border.
		
		Cheers
		STEVE
		
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