[Talk-us] Park Boundary tagging

stevea steveaOSM at softworkers.com
Fri Mar 1 22:31:20 UTC 2013

Greg Troxel <gdt at ir.bbn.com> writes:

>I agree that boundary=national_park is confused, and to first order 
>I think we should get rid of it.  The first question is whether it's 
>tagging a boundary, which is a line feature, or whether it is 
>tagging the polygon.  If it's a boundary, it should be tagging the 
>line feature, and it's a bug for that to affect the rendering of the 
>area.  But that's how it is used now.

OSM's wiki lists elements (primitives) as points, ways (open 
polyline, closed polyline or area), and relations, all of which can 
have tags, plus relations have members with optional roles.  OK, we 
understand this.

OSM's wiki lists seven values for the boundary key:  administrative 
(where admin_level is an associated key), maritime, national_park, 
political, postal_code, protected_area, and "user defined," where 
taginfo lists all of the above being used ("administrative" makes up 
over 91% of boundary= usage), plus hundreds of others.  Also, taginfo 
lists boundary=national_park as being used about 11,000 times (1.25% 
of the ~one million times the boundary tag is used): 
boundary=national_park is both documented and well-used.

Each of those seven values for key boundary is documented to be of 
element "area" (with the exception of boundary=user defined, where it 
is given greater freedom to be assigned to primitives of points and 
open polylines).  So for Greg to assert that "if it is a boundary, it 
should be tagging the line feature, and it's a bug for that to affect 
the rendering of the area" just flatly contradicts our wiki.  To 
summarize, the boundary tag absolutely positively defines areas, not 
"line features" (ways as open polylines).  I completely disagree with 
Greg's conclusion above, but I'm still listening to and participating 
in this discussion.

>I think national parks should have landuse=conservation 
>leisure=nature_reserve like all other conservation/human-use-also 

The wiki page for tag "Conservation" is just a stub and points right 
back to "boundary=national_park" and "boundary=protected_area."  The 
latter is actually a fairly well-developed scheme, though new-ish to 
OSM, even if it is not well-supported by the standard (mapnik) 
renderer.  As I mentioned, the former (boundary=national_park) IS 
well-supported by mapnik.

>If we do want to tag park boundaries, I think we should step back 
>and ask why, and then have a coherent park boundary scheme. 
>national parks, state parks, municipal parks are in some sense 
>really all the same,
>except different levels of government own and administer them.  I 
>agree that national parks are a bigger deal socially, but I don't 
>see a big enough distinction to have a special top-level tag.

Here, Greg and I agree:  a coherent park boundary scheme is what we 
are discussing, and it needs improvement in both development of a 
sensible tagging syntax, and support for that in mapnik render rules. 
That tagging syntax will likely include harmonization of the 
following "top-level" tags:  boundary (including the "combo tag" 
admin_level), leisure, and possibly landuse, though by no means is 
this list meant to be complete.  Accordingly, I have changed this 
thread title from "Wilderness Data" to "Park Boundary tagging."

>I think it's also confusing for our international comrades that we 
>use park in two totally different senses:
>   national park, which is about a balance conservation/preservation and access
>   local park, which is often a "leisure=recreation_ground" and not 
>necessarily conservation (ball fields, etc.)
>   local consevation area, which is not called park, even though it's 
>far more like a national park in character (but not scale) compared 
>to a local park

So let's collect tags and do a "here's what's used" vs. "here's what 
we want to convey" matrix.  I won't start that more technical aspect 
now, because I agree with you (again) that we should "step back and 
ask why" we want to tag park boundaries.  So, why do we?  Well, one, 
to show that we conserve land.  Two, to delineate boundaries where we 
might recreate on that land.  Beyond those, it blurs into nearly 
endless detail.  Well, OK, three:  we might also discuss (again I'm 
agreeing with Greg) that "different levels of government own and 
administer (parks)."  If we stick to those basic tenets, I think we 
can do this.

The new thread begins.  Let's discuss.


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