<div dir="ltr"><div>I render the things that OSM shows as cliffs, because sometimes surprises lurk between the contour lines. Otherwise, when I care, on my own maps I render elevation contours (and hence have no use for the cliff height in the data base). In a spot like <a href="https://kbk.is-a-geek.net/catskills/test3.html?la=42.1876&lo=-74.0397&z=14">https://kbk.is-a-geek.net/catskills/test3.html?la=42.1876&lo=-74.0397&z=14</a>, it's pretty obvious that there are cliffs about.<br><br></div>I do like the idea of having some sort of object for cuts and fills, because they're important features that often aren't in the elevation databases. Highway and rail embankments would kind of come along for the ride.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 29, 2016 at 6:08 PM, 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_3215297305207488891moz-cite-prefix">I would hope that a scheme can be had
      that is one sided - and the same for cliff, embankment, cutting
      etc. <br>
      <br>
      As such it should be one sided. After all another side could have
      a different slope/area. A single sided scheme could be used for 2
      sided or multi sided structures by many separate one sided OSM
      entries, as many entries as required to represent the structure.
      In this way the name of the structure has less relevance ... when
      does an embankment become a cutting? A cutting a cliff? If the
      result is the same .. then it does not really matter what it it
      called, avoids arguments of things like masts vs tower, monument
      vs memorial. <br>
      <br>
      One rendering, not OSM based, has cliffs in pink, the top with
      spikes pointing downwards and the vertical rise stated as a number
      in meters. <br><div><div class="h5">
      <br>
      On 30-Nov-16 09:57 AM, Lorenzo "Beba" Beltrami wrote:<br>
    </div></div></div><div><div class="h5">
    <blockquote type="cite">
      <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" target="_blank">http://www.navecorsara.it/wp/<wbr>wp-content/uploads/2010/01/<wbr>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" target="_blank">http://bur.regione.veneto.it/<wbr>resourcegallery/photos/465_<wbr>Guarda%20Veneta_ro_Panorama%<wbr>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%2<wbr>9#/media/File:Embankment_1_%28<wbr>PSF%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="m_3215297305207488891HOEnZb">
              <div class="m_3215297305207488891h5">
                <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_3215297305207488891m_1585881037483698941m_-6595638630347841077m_5528073053367767952moz-cite-prefix">Not
                                    all embankment have 2 slopes <br>
                                  </div>
                                </div>
                              </blockquote>
                              <div><br>
                              </div>
                            </span>
                            <div class="m_3215297305207488891m_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_3215297305207488891m_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_3215297305207488891m_1585881037483698941h5">
                                <div class="m_3215297305207488891m_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_3215297305207488891m_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_3215297305207488891m_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>
                                                <br>
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                                                <br>
                                              </blockquote>
                                            </div>
                                            <br>
                                          </div>
                                          <br>
                                          <fieldset class="m_3215297305207488891m_1585881037483698941m_-6595638630347841077m_5528073053367767952mimeAttachmentHeader"></fieldset>
                                          <br>
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</pre>
    </blockquote>
    <p>

    </p>
  </div></div></div>


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</blockquote></div>
</div>
</div></div>
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</blockquote></div>
</div>


<fieldset class="m_3215297305207488891mimeAttachmentHeader"></fieldset>
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</pre>

</blockquote><p>
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<br></blockquote></div><br></div>