<div dir="ltr">It makes sense that a road embankment have only one slope.<br><br>Perhaps for a levee[1] we need a specific tagging system because a levee has always two slopes.<br><br>I'm native of the Po Valley where levees are along every river (Volker can confirm it ;) ).<br>A levee for flood prevention could be simple[2] but even a wide and complex feature[3] to map.<div><br></div>Lorenzo<br><br>[1] <a href="https://en.wikipedia.org/wiki/Levee#River_flood_prevention" target="_blank">https://en.wikipedia.org/wiki/<wbr>Levee#River_flood_prevention</a><br>[2] <a href="http://www.navecorsara.it/wp/wp-content/uploads/2010/01/Stirone_argine_1-580x435.jpg">http://www.navecorsara.it/wp/wp-content/uploads/2010/01/Stirone_argine_1-580x435.jpg</a><br>[3] <a href="http://bur.regione.veneto.it/resourcegallery/photos/465_Guarda%20Veneta_ro_Panorama%20con%20argine.jpg">http://bur.regione.veneto.it/resourcegallery/photos/465_Guarda%20Veneta_ro_Panorama%20con%20argine.jpg</a><br></div><div class="gmail_extra"><br><div class="gmail_quote">2016-11-29 23:28 GMT+01:00 Kevin Kenny <span dir="ltr"><<a href="mailto:kevin.b.kenny+osm@gmail.com" target="_blank">kevin.b.kenny+osm@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>'Embankment' is frequently used for a built-up structure on a steep hillside that keeps a road, railroad, or similar feature from sliding into a gorge or river. See <a href="https://en.wikipedia.org/wiki/Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png" target="_blank">https://en.wikipedia.org/wiki/<wbr>Embankment_%28transportation%<wbr>29#/media/File:Embankment_1_%<wbr>28PSF%29.png</a> for an illustration from Wikipedia. Except for the portion crossing the tributary stream, the road in the picture is clearly NOT banked on the uphill side, so the embankment here is what Warin was describing as 'one-sided.'<br><br></div>Locally to me, this is the commonest sense of the word. <br><br>I am a native speaker of American English, and I live in terrain heavily sculpted by the glaciers of the last Ice Age, where highway and railroad embankments are relatively common.<br></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 29, 2016 at 4:34 PM, Volker Schmidt <span dir="ltr"><<a href="mailto:voschix@gmail.com" target="_blank">voschix@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span>On 29 November 2016 at 22:03, Warin <span dir="ltr"><<a href="mailto:61sundowner@gmail.com" target="_blank">61sundowner@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div class="m_1585881037483698941m_-6595638630347841077m_5528073053367767952moz-cite-prefix">Not all embankment have 2 slopes <br></div></div></blockquote><div><br></div></span><div class="m_1585881037483698941m_-6595638630347841077m_5528073053367767952moz-cite-prefix">To my understanding of the English term, an "embankment" is the equivalent of dyke or levee and is a long, narrow man-made elevation. Therefore they always have two slopes of opposite directions (leaving out the ends)<br><br></div><div class="m_1585881037483698941m_-6595638630347841077m_5528073053367767952moz-cite-prefix">What Martin proposes should get a different tag name to distinguish it from an embankment. The term "on-sided enmbankment" is used in OSM for this, but I do not like it at all. I strongly recommend to use a different tag name. I used "slope" as this is the term used to describe the inclined flanks of levees (=embankments).<br></div><div><div class="m_1585881037483698941h5"><div class="m_1585881037483698941m_-6595638630347841077m_5528073053367767952moz-cite-prefix"><br><br>
Length - simple set as the length of the way. Cliffs are tagged as
a single way at the top of the cliff, with the right hand side
being 'downwards' when facing the direction of the way. <br>
<br>
Vertical rise - could be tagged with the height key.. this can
vary over the length of the feature (I have found this on some
maps as a number in meters ... assumed to be the maximum vertical
locally rise in meters) To accomodate teh change in vertical
height .. put the height on individual nodes? <br>
<br>
Slope - or in OSM terms 'incline'. This in OSM is entered as a way
along the top where the slope would be minimal and not what 'we'
want to describe. ... as cliffs, cuttings and embankments are best
described this way I think incline may not be the best thing to
tag? Humm stairs are described using the incline key ... but on a
way that goes up .. leaving the top and bottom free of this. So
maybe a top and bottom way .. with a simple way from bottom to top
containing the incline information? <br>
<br>
While the 'top' and 'bottom' of natural features can be a bit
fuzzy they are features that should be mapped. Definition?
Something for a geologist? Along the lines of the line formed by
the intersection of the average slope of land before the change to
the average slope of land after the change ( the change being the
cliff, embankment or cutting)?<div><div class="m_1585881037483698941m_-6595638630347841077h5"><br>
<br>
<br>
<br>
<br>
On 30-Nov-16 01:25 AM, Volker Schmidt wrote:<br>
</div></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000"><div><div class="m_1585881037483698941m_-6595638630347841077h5">
<blockquote type="cite">
<div dir="ltr">
<div>If you want to micromap slopes you should create a new key
"slope" or something similar. An embankment has two slopes. It
is equivalent to dyke or levee. The one-side embankments that
are defined in the OSM wiki, are in reality slopes and should
be retagged accordingly.<br>
<br>
</div>
Independently of the name used fo the tag I see the prblem of
defining where the slope starts, normally these are rounded
features.<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On 29 November 2016 at 13:48, Martin
Koppenhoefer <span dir="ltr"><<a href="mailto:dieterdreist@gmail.com" target="_blank">dieterdreist@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>Currently we are mapping only one side of the
embankment (I think it's the upper side, but am
not sure if the wiki says this explicitly), with
the direction. What we would IMHO need is a way
to map the lower side as well and to combine
both. A closed polygon will not work I believe.<br>
<br>
</div>
The obvious solution that comes to mind is a new
relation type: in case the upper end is mapped,
draw a new way for the lower end and combine both
with a relation (possibly assigning roles like
upper and lower, maybe also draw lateral ways
(ways that connect the ends of the upper and lower
ways and defines their shape) in cases they are
not straight). (The type=area relation does this)<br>
<br>
</div>
Maybe it could also be done without the relation,
simply by tagging the upper and lower ways
accordingly, and connect them at least at one of
their ends with an explicit lateral way (and
respective tags). This would require from the data
user to topologically search for the embankment area
in order to be able to render it (or make other
use).<br>
<br>
</div>
What do you think, which representation is better? Are
there alternatives?<br>
<br>
</div>
Cheers,<br>
</div>
Martin<br>
</div>
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</blockquote>
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