[OSM-talk] Abuse of natural=cliff tag

Sarah Hoffmann lonvia at denofr.de
Tue Sep 10 22:17:14 UTC 2019


On Fri, Sep 06, 2019 at 02:42:06PM +0200, Vladimir Vyskocil wrote:
> Around this area : https://www.openstreetmap.org/#map=16/50.9034/14.2763 <https://www.openstreetmap.org/#map=16/50.9034/14.2763> there is a flagrant misuse and abuse of the usage of the natural=cliff tag. It is used to map the iso altitude lines and not real cliff as stated in the WIKI :
> A cliff <http://en.wikipedia.org/wiki/en:cliff> is a vertical or almost vertical natural drop in terrain topography as it occurs for example in form of coastal cliffs or escarpments. The face of the cliff usually consists of bare solid rock but can occasionally also consist of clay, compacted sand, ice or other solid materials.  

I know that area very well and I can assure you, that natural=cliff is no misuse
under this definition. The area is full of rock towers like those:

That's what you see on the map.

> I already removed the natural=cliff ways mapped by MichaOSM after asking him to fix this but without response the changeset comment was : 
> "Felsen, Riffe, Topografie nach GeoSachsen digitale Geländemodellhoehenlinien 2.5m, digitales Geländereliefmodell, DTK10, topografische Karte”
> For example this changeset : https://www.openstreetmap.org/changeset/66373825#map=15/50.9016/14.3093 <https://www.openstreetmap.org/changeset/66373825#map=15/50.9016/14.3093>
> It say that it used a 2.5m topographic map to map all these false cliffs in this area, he was mapping the topography (MNT) and this is forbidden in OSM.

You missunderstood, he was mapping rock edges. A terrain model is more helpful
for that task than arial imagery. We have permission to use the terrain model
for OSM as far as I know.

I would kindly request that you reinstate deleted natural=cliffs for
the moment. If you are still not convinced from the photo above that the
tagging is correct then we need to have a fundamental discussion first about
how to tag these kind of rock towers. But that would rather be something for
the tagging mailing list (or talk-de if you want to get the locals involved).


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