[Tagging] Map a divide?

Joseph Eisenberg joseph.eisenberg at gmail.com
Fri Oct 5 01:06:15 UTC 2018

> I do agree that a true ridge line may not point uphill all the time, but still be a single ridge.
> There is also no mention of that rule in the original approved proposal. Looking at the history of the article, that rule was added in January 2018, following a short, well "discussion" about how a ridge could be rendered.
> Thank you for noticing this! I had just looked at the proposal page
yesterday and was wondering where the directional thing came from.
It will make my life much easier if I can draw a whole named ridge as one
way, instead of splitting it at each topographical saddle and peak!
In Northern California, many named ridges are long, but are considered one

> Am 4. Oktober 2018 16:46:19 MESZ schrieb Kevin Kenny <kevin.b.kenny at gmail.com> <kevin.b.kenny at gmail.com>:
> In some maps that I render, I want to show the divide between a couple
> of major river basins. (I have a good DEM for the area in question and
> can derive the line readily.)
> In light of the recent thread on topographic prominence, I wonder if
> this is sufficiently interesting information at least to push it to
> OSM.
> Re: the original question, I've been thinking of this myself.

Besides natural=ridge, which is an approved feature, but meant for
individual ridges, there is also the proposed feature natural=mountain_range
I believe this is the appropriate tag for the line formed by the crest of
the Appalachian Mountains, or the Sierra Nevada and Cascade crests in the
It could either be used as a way that follows the line of each individual
ridge, or you could use a relation and add each of the ridges.

I think natural=divide could be appropriate for a clearly defined drainage
divide which is not a mountain range; eg a range of hills or a series of
low ridges?
But there's no proposal page or wiki page yet.

On the previous discussion, several people warned that we should not
attempt to map all divides between water drainage areas, because there are
some flat areas like plateaus or plains where the drainage is not clear,
even if you survey the area in person or check good satellite imagery. But
if there is a clear ridgeline, that should be verifiable. I'm not certain
of the situation in the Catskills.
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