# [Tagging] Map a divide?

Joseph Eisenberg joseph.eisenberg at gmail.com
Fri Oct 5 01:18:49 UTC 2018

```That divide is, ipso facto, a ridge line, because water flows downhill
> - it is a line that's higher than the basins on either side. It runs
> of but little prominence) for the length of the divide.
>

Agreed. But I'd keep natural=ridge for individual named ridges (which may
have a few named peaks and saddles along it's length)
And use natural=mountain_range for the much larger features which continue
several or many named ridges and peaks and saddles.
Or natural=divide

> Can we agree that https://www.flickr.com/photos/ke9tv/9514469053,
>
https://www.flickr.com/photos/ke9tv/9764660284,
> https://www.flickr.com/photos/ke9tv/10031459724 and
> https://www.flickr.com/photos/ke9tv/14799708048 are all indeed views
> of a ridge?
>

Yes, agreed. The page for natural=ridge shows a rather low, gentle hill as
an example of a ridge.

Open question - which I'll resolve for myself - is how much
> topographic prominence to use when labeling peaks and saddles.  I
> think I'll probably follow the local hiking clubs, and say, '150 feet
> (about 45 m) of prominence, and 1 km separation' for mapping peaks and
> their key cols, and at this point I care about the key cols mostly so
> as to keep the topology of the divide continuous - although I'll
> surely map the names of the saddles where I know them!
>

I'd map all named peaks that have any topographical prominence, but include
the prominence=* in meters.

For example, the most visually significant mountain peak in my hometown is
"Lower Devil's Peak";
It rises over 600m from the valley floor, but only has about 15 meters of
topographical prominence,
because it connects to a high ridge leading to "Middle Devil's Peak" and
"Upper Devil's Peak" (both more prominent).

If you know the topographical prominence it's really helpful to add, to
show that this is a minor sub-peak.