[Tagging] Comparison of tag support: Mapnik, Osmarender, Potlatch, JOSM, Kosmos, Map Features (wiki)

Steve Bennett stevagewp at gmail.com
Mon Dec 14 09:05:21 GMT 2009

On Mon, Dec 14, 2009 at 12:23 PM, Ulf Lamping
<ulf.lamping at googlemail.com> wrote:
> Where does proposed= is prohibited in the wiki?!?

I was confused. Some day I will find the page that made me think that.
It was a phrase like "under no circumstances map proposed roads", but
maybe it was in some weird context.

>> Yeah, and I think there is an unfortunate problem where the
>> wiki/mappers don't want to tell the renderers what to do, and the
>> renderers don't want to tell the mappers how to map.
> And I guess this is a good thing.

I think it would be even better for the mappers to give guidance to
the renderers, like "This tag should be rendered distinctly from that
tag" or "the combination of x,y,z should be rendered identically to
tag w".

> I guess this is also a lack of man power. Don't underestimate the amount
> of time that is needed here. Having the actual usage numbers from e.g.
> OSMDoc[1] would really help here.

Yeah, I was just having a look at tagwatch, which has usage numbers
for the few hundred tags that are explicitly referred to in the wiki.
Can't see how to get global numbers though - only by continent. I may
try and integrate these numbers, but I'm a bit wary of what they mean.
(eg, one bulk import of 10,000 nodes with a certain tag should not
necessarily "count" for more than 8,000 nodes created manually by 20
different mappers.

> The voting process was actively torpedoed by some people some time ago :-(

Oh, do tell?

>> It might be better to think in terms of "core" tags and "specialist"
>> tags or something. If something is core, we expect all decent
>> renderers to render it.
> How do you enforce this with people doing the renderer maintenance in
> their spare time? ;-)

I didn't say enforce! All I'm saying, is you give a list of
priorities, like "all renderers should support these tags". Just like
when you "saw what the other renderers are doing", I think programmers
would be inspired to implement that kind of list. And obviously
certain kinds of tags can be implemented very easily, just with a
colour or whatever, while others are harder.

> I think its a much better way to display each renderer maintainer: Look,
> these are the tags that x, y and z are rendering and you don't. Maybe
> you've just missed it? And also the other way round: No one else is
> rendering x=y, maybe this is a bug?

Yep. And the one I'm concerned about, "renderer X supports tag A,
renderer Y supports tag B, yet A is pretty similar to B". The mass of
landuse=* and natural=* are pretty haphazard - I don't think any sharp
distinctions are being recorded.

> As mentioned already, the next best step IMHO would be to have the
> actual usage numbers from OSMDoc.
> However, it's up to you what you do with your free time :-)

Doesn't mean I don't want suggestions!

> [1] http://osmdoc.com/de/tag/sport/

Is there a way to get a big dump from this? I can only see a way to
access one key at a time.

Fascinating stuff, though. I note the usage of
"leisure=nature_reserve", "natural_reserve" and "nature_preserve".
Also, 457 leisure=swimming_pool, but 7188 sport=swimming.


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