[Tagging] What about a disused quarry and historic surface mining?

Tom Pfeifer t.pfeifer at computer.org
Mon Jan 9 21:16:55 UTC 2017


On 09.01.2017 21:23, ael wrote:
> On Mon, Jan 09, 2017 at 02:00:58PM +0100, Tom Pfeifer wrote:
>> On 09.01.2017 13:15, ael wrote:
>> Please do not use "disused=yes" as it is considered troll-tagging, first
>> saying it is simething, and in the next line negating it.
>
> I don't think that is a natural interpretation. It is perfectly clear in
> the case of a disused quarry. It is still a quarry. But it is no longer
> in use. In a few cases it may have a new purpose, but it is still a
> quarry in any normal sense.

This is certainly not that black and white, and depends on perspective.
When it is fully re-naturated and filled with water I would no longer 
call it a quarry. In the end, what would you want to render, the old 
black quarry or the new blue lake? Hammer icons on the lake?

> I think I tried disused:landuse=quarry, but as I recall it was then not
> rendered on the standard map. I am all against tagging for the renderer
> in principle, but when such major features are not shown, it is
> ridiculous and a hazard. Theses particular quarries have sheer faces
> some of which are not fenced off.

If the quarry leaves cliffs you can map them, and the cliff is rendered. 
It's the same hazard as any natural cliff then.

We all have long list of features that we would like it see rendered for 
various reasons, but the correctness of the database should have 
priority. Then you can always render your own map, showing these 
features correctly.

>> man_made=bridge is rendered on the main carto map. If the bridge outline of
>> a major bridge is not in the database, it's the mappers' fault, not the
>> renderers'.
>
> Are you suggesting that I pollute the database with invented features?

The bridge is not an invented feature, if it exists in reality. If you 
have the length of the bride from the old track, you can estimate the 
width, and add a tag like source=estimate. So the next mapper can run 
around with a GPS receiver and refine, and eventually we get an aerial 
image from winter with less leaves and can refine even more. That's how 
OSM works.

> I have mapped several of these bridges which are under thick tree cover

There are some techniques to walk towards each corner from a distance to 
get better bearings.

> A bridge is a bridge and is a major feature regardless of whether it is
> still in use for its original purpose.

Yes it is and therefore we are happy that the man_made tag is rendered 
in carto. Just map it as best as you can, describing the quality you 
achieved, and things will improve over time.

tom




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