[OSM-talk] National borders - mapnik

[Steve Chilton]

See example from UK: http://dev.openstreetmap.org/~steve8/borders.jpg
Border between countries England and Scotland is one way (actually probably several ways), tagged admin_level=2.
Border between counties Cumbria and Northumberland is another way/s, tagged admin_level=6.
Implicitly the country border is part of the collection of ways that make up the Cumbria county border.
There is only one border there, and there only needs to be one "way".
NB: If you want polygons for areas you probably have to post-process the data to compile them or use relations to group them.
 
Cheers
STEVE

	-----Original Message----- 
	From: blodulv at gmail.com on behalf of Beau Gunderson 
	Sent: Wed 5/28/2008 9:14 PM 
	To: Steve Chilton 
	Cc: talk at openstreetmap.org 
	Subject: Re: [OSM-talk] National borders - mapnik
	
	
	Please clarify one thing:
	
	   "any border that is both a state and national border should be tagged at the highest level (in this case national, admin_level=2)"
	
	To me this sounds like there is just one way for the state/national border... but...
	
	   "and the state borders will come in too, with their appropriate style."
	
	This sounds like there are two ways, one for the state border and one for the national border.
	
	This seems to make the most sense to me given the second sentence quoted above.
	
	
	Beau
	
	
	On Wed, May 28, 2008 at 2:06 PM, Steve Chilton <S.L.Chilton at mdx.ac.uk> wrote:
	

		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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