[Tagging] Additional detail of Levee mapping via embankments
johnw at mac.com
Mon Nov 18 00:17:59 UTC 2019
> On Nov 16, 2019, at 7:50 PM, Andy Townsend <ajt1047 at gmail.com> wrote:
> A complicated scheme dreamt up here isn't going to get taken up by anyone.
I took these 3 pictures yesterday while out cycling: https://imgur.com/gallery/Wqc5Ems <https://imgur.com/gallery/Wqc5Ems>
The largest of the 8 levees I rode on is 140m wide (edge to edge) where I took these pictures, according to an online imagery measuring tool. they are about 3 stories tall. the north side levee is 100M wide. These are all built on flat open ground, the levees 100% man-made. the river is 600m wide here during a typhoon.
148&60m (both levees total width, near a river junction)
54&30m (smaller river)
40&50m (smaller river)
65&42-70m (they are widening them, a demolished house foundation seen here in maxar imagery https://www.openstreetmap.org/way/746507486 <https://www.openstreetmap.org/way/746507486>).
much farther upriver near my town, where the levee on a tributary begins, they are a modest 40 & 30m wide where they sprout out of foothills the river has cut.
I agree that complicated schemes won’t get used, which is why I want the smallest usable method necessary **for people who want to add more detail in addition to existing schemes** , something that scales similar to how we map businesses (pin, building, landuse) depending on how much detail you wish to add.
if you don’t feel the need to map an embankment in such detail, don’t. if it is too small, don’t. I don’t want to create a scheme that replaces the current embankment/cutting/ levee, but is on top of current schemes, and allows you to map their extent **if you wish to**.
When things are huge, you *have to* have the ability to represent *anything* in OSM by border or area. If I was living back in San Diego, the cuttings for the freeway are the only cuttings I can think of worth mapping as an area. here in Japan, embankments / cuttings/ levees are everywhere. One levee bank is wider than most railway corridors - and we have an area for those, despite that the train tracks already being mapped. We understand that the area of the corridor is useful, to represent landuse and as a defacto barrier.
The same is true for large embankments/levees.
For very large features *of any type* in OSM, they their area needs to be represented *somehow* in OSM.
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