[OSM-talk] Boundary rendering bug

Toby Murray toby.murray at gmail.com
Thu Feb 10 05:24:50 GMT 2011


Apparently I failed to communicate clearly in my first email. Let's
try this again.

Boundary relations tagged with admin_level=6 and member ways WITHOUT
admin_level tags are rendered starting at z9

Boundary relations tagged with admin_level=6 *and* member ways WITH
admin_level=6 aren't rendered until z11

This seems like a discrepancy.

You can see county borders being rendered at z9 in the link from my first email:
http://www.openstreetmap.org/?lat=41.326&lon=-107.747&zoom=9&layers=M

Toby


On Wed, Feb 9, 2011 at 9:43 PM, Daniel Sabo <danielsabo at gmail.com> wrote:
> Ah, I think I see what you're saying. What zoom level do you expect it to render at? The current stylesheet doesn't render county boundaries until z11, period.
>
> My reading of the stylesheet [1] is that by not specifying an admin level you're abusing the "admin-other" category and making it render at lower zoom. If you want counties to intentionally render at z9 good luck getting someone to change the style :P. I do agree that it would look nicer if it rendered them at lower zoom.
>
> - Daniel
>
> [1] http://svn.openstreetmap.org/applications/rendering/mapnik/inc/layer-admin.xml.inc
>
> On Feb 9, 2011, at 6:36 PM, Toby Murray wrote:
>
>> What you say makes perfect sense. But you got my situation wrong. When
>> admin_level=6 *IS* specified on the way it doesn't render until z11.
>> When it is only on the relation but NOT on the way then it renders at
>> z9.
>>
>> Toby
>>
>> On Wed, Feb 9, 2011 at 8:08 PM, Daniel Sabo <danielsabo at gmail.com> wrote:
>>> It's not really a bug, if you have the following setup:
>>>
>>> Member way:
>>> boundary = administrative
>>>
>>> Relation:
>>> boundary = administrative
>>> admin_level = 6
>>>
>>> What you're telling mapnik is that there are two boundaries, one is admin_level 6, the other is admin_level undefined. The admin 6 one will render at z11 or closer, the undefined one renders at z9 to z11.
>>>
>>> To map the boundary as a relation you should have:
>>>
>>> Member way:
>>> no boundary tags (that includes the boundary name)
>>>
>>> Relation:
>>> boundary = administrative
>>> admin_level = 6
>>> name = Something
>>>
>>> Boundary relations are just specialized multipolygons once they reach the renderer so all the rules here apply: http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Usage
>>>
>>> - Daniel
>>>
>>> On Feb 9, 2011, at 11:27 AM, Toby Murray wrote:
>>>
>>>> Well like I said, leaving the admin_level=6 on the ways is indeed
>>>> tagging for the renderer. However isn't there still a mapnik bug here
>>>> no matter how you look at it? Shouldn't an admin_level=6 boundary be
>>>> rendered at the same zoom level whether it is mapped as a relation or
>>>> as a way?
>>>>
>>>> Toby
>>>>
>>>> _______________________________________________
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>>>
>>>
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>>>
>
>
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