[Tagging] [OSM-talk-be] how to map a fr:talus?

[André Pirard]

On 2017-11-23 17:26, joost schouppe wrote:
> 2017-11-23 16:48 GMT+01:00 André Pirard <A.Pirard.Papou at gmail.com
> <mailto:A.Pirard.Papou at gmail.com>>:
>
>     Hi,
>
>     I'm looking for how to map what is called in French a talus
>     <http://www.cnrtl.fr/definition/talus> (Google's translation).
>     I would call this a 1.8m simple step running for some reason for
>     several 100s meters across meadows.
>     Steep slope. There are "top of slope" and "bottom of slope" lines.
>     Rest is perfectly flat either side.
>     It might be the remnants of a old canal's bank whose other side
>     would have been eroded by the often overflowing nearby river.
>     A "talus" made of plain ground is often frequent at one side of a
>     path or track.
>     According to the wiki, it's not a "scree" nor a "shingle". It's
>     much less matter specific.
>     So what?
>     I'll use "scree" unless/until I hear of better for a French talus.
>
>     Cheers
>
>     André.
>
> I'm not entirely sure this is what you have in mind, but in the cases
> where it is associated with roads, I've seen historic=hollow_way (when
> the slope is caused by the fact that there's an old road), and
> "embankment" or "cutting" when the slope is deliberatly constructed.
> In other cases, I've seen what I think you describe mapped as
> natural=cliff, which is obviously wrong, but does get the message
> accross. For example where sand or rock was quarried this is common to
> see on the map. I'm hoping someone has seen better ideas.
Thanks for all your fast answers from which I had to choose the first
one to reply to.
A photo was asked. I might go back there to make one, but you wouldn't
see more that the surface of a meadow looking like this on a long
distance, at varying steepness and width.
               _________
          /
         /
________/

It can be seen on this map share
<http://geoportail.wallonie.be/walonmap#BBOX=233801.45736786586,233864.69291100363,138369.75440413086,138396.60966617474#SHARE=5EAB0363BC0C4A92E053D0AFA49D3CB8>,
pan it to the left and right.
The two striped, faint lines are the upper and lower edges (rims,
levels) from the BE SPW(allonie) PICC numerical imagery
<wms:http://geoservices.wallonie.be/arcgis/services/TOPOGRAPHIE/PICC_VDIFF/MapServer/WmsServer?SERVICE=WMS&VERSION=1.1.1&FORMAT=image/png8&TRANSPARENT=TRUE&REQUEST=GetMap&STYLES=&SRS=%7Bproj%7D&WIDTH=%7Bwidth%7D&HEIGHT=%7Bheight%7D&BBOX=%7Bbbox%7D&LAYERS=0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29>
(JOSM) overlay allowing me to map it. As you zoom out, you will see that
the aerial photo is darker along that line.
The Cartoweb background (Fond de Plan) draws it as the typical "behind
which to hide" line of old military maps.
Well, in OSM parlance, it's not a cree because there is no cliff (1),
not a shingle because there is no sea and not an embankment because
there is no road to be an attribute of.
Well, as I said it, what I'm facing seems to be, as I found more
specifically, the remnants of this old canal @ N°12
<https://fr.wikipedia.org/wiki/Projet_de_canal_Meuse_et_Moselle#N.C2.B012_Devant_Rosi.C3.A8res>.
The river often overflows as high as above the road. When the water goes
back, it washes the left bank of the canal towards the river but the
right bank is mostly just overflown.

So, there's nothing in OSM for that precisely.
Would man_made=dyke be the most resembling and acceptable with an
explanation note?

Thanks and TIA,
Cheers

André.


(1) there's a very beautiful one, but at the other side of the river,
called "La Roche aux Faucons" (Falcons' Cliff).

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