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<div class="moz-cite-prefix">Not all embankment have 2 slopes .. nor
does a 'slope' describe all of the properties of an embankment.
The same problem exists for a 'cliff' and a 'cutting' ... and
stairs that cover a large area. So use what has been done for them
as a guide. <br>
<br>
What are the key properties of these features ... <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)?<br>
<br>
<br>
<br>
<br>
On 30-Nov-16 01:25 AM, Volker Schmidt wrote:<br>
</div>
<blockquote
cite="mid:CALQ-OR6me-7231c9EZ0GYmhsHRW-cB4wGFf3ePuqC=UE_fk1Qw@mail.gmail.com"
type="cite">
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<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 moz-do-not-send="true"
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>
<br>
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</blockquote>
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