It makes sense that a road embankment have only one slope. Perhaps for a levee[1] we need a specific tagging system because a levee has always two slopes.
I'm native of the Po Valley where levees are along every river (Volker can confirm it ;) ). A levee for flood prevention could be simple[2] but even a wide and complex feature[3] to map. Lorenzo [1] https://en.wikipedia.org/wiki/Levee#River_flood_prevention [2] http://www.navecorsara.it/wp/wp-content/uploads/2010/01/Stirone_argine_1-580x435.jpg [3] http://bur.regione.veneto.it/resourcegallery/photos/465_Guarda%20Veneta_ro_Panorama%20con%20argine.jpg 2016-11-29 23:28 GMT+01:00 Kevin Kenny <[email protected]>: > '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 https://en.wikipedia.org/wiki/ > Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png > 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.' > > Locally to me, this is the commonest sense of the word. > > 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. > > On Tue, Nov 29, 2016 at 4:34 PM, Volker Schmidt <[email protected]> wrote: > >> >> >> On 29 November 2016 at 22:03, Warin <[email protected]> wrote: >> >>> Not all embankment have 2 slopes >>> >> >> 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) >> >> 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). >> >> >> 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. >> >> 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? >> >> 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? >> >> 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)? >> >> >> >> >> >> On 30-Nov-16 01:25 AM, Volker Schmidt wrote: >> >>> 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. >>> >>> Independently of the name used fo the tag I see the prblem of defining >>> where the slope starts, normally these are rounded features. >>> >>> On 29 November 2016 at 13:48, Martin Koppenhoefer < >>> [email protected]> wrote: >>> >>>> 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. >>>> >>>> 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) >>>> >>>> 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). >>>> >>>> What do you think, which representation is better? Are there >>>> alternatives? >>>> >>>> Cheers, >>>> Martin >>>> >>>> _______________________________________________ >>>> Tagging mailing list >>>> [email protected] >>>> https://lists.openstreetmap.org/listinfo/tagging >>>> >>>> >>> >>> >>> _______________________________________________ >>> Tagging mailing >>> [email protected]https://lists.openstreetmap.org/listinfo/tagging >>> >>> >>> >>> _______________________________________________ >>> Tagging mailing list >>> [email protected] >>> https://lists.openstreetmap.org/listinfo/tagging >>> >>> >> >> _______________________________________________ >> Tagging mailing list >> [email protected] >> https://lists.openstreetmap.org/listinfo/tagging >> >> > > _______________________________________________ > Tagging mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/tagging > >
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