Proposed features/peak

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Enhancing natural=peak tag
Status: Proposed (under way)
Proposed by: kocio
Tagging: peak=mountain, hill, knoll/hillock (+ man_made=peak)
Applies to: NodeArea
Definition: Tags enhancing natural=peak
Rendered as: Peak mapnik.png
Drafted on: 2014-07-06

Proposal

I'd like to enhance the *=peak tag with three sub-tags:

  • peak=mountain
  • peak=hill
  • peak=knoll/hillock

They should be chosen according to the relative height above the surrounding terrain - not the elevation above the sea level. The distinction between those land forms is more or less subjective (see the hill definition on Wikipedia), but I think we don't need to stick to the numbers. However we can give a hint to tag the hills when the height x is like:

100 m < x < 300 m

and tag all the higher ones as mountain and all the smaller ones as knoll/hillock.

Knoll/hillock terminology (see the Wikipedia definition) is dependent on US/UK usage of words. I like the "knoll" more, since it is shorter and more distinct, but since we have a lot of UK background (like prominent "highway" tag), it is still possible to use the "hillock".

Important thing to consider is adding the twin top-level tag "man_made=peak", since many smaller peaks are not of natural descent. This tag is very rare now (see the usage statistics), but it exists. When the descent is not known, we can leave it for mappers to choose reasonably, since we can't have peaks of undecided type.

Rationale

As the project is getting bigger, we need to make some refinements to the already existing, but very broad tags scheme. Especially the micromapping phenomenon makes it important to separate some smaller, but still visible and useful land forms, from the typical alpinist/hiking aims. This is the question of proper scaling - in the mountains 2 m knoll would be just a small distortion, but in the micro- scale on the flat surface it can be a good orientation point. They should not be mixed, as it is done now: look for example at the Berlin map "polluted" with hills/knolls even at z11, visually suggesting it's a mountain city.

Additional, minor role of tagging such smaller peaks is helping to expand a bit current (poor) state of representing land relief on OSM.

"Hill" and "knoll" are listed as 1.9 and 1.10 in the IOF document "Control Descriptions symbols only". There is a definition of "111 Knoll", "112 Small knoll" and "113 Elongated knoll" in International Specification for Orienteering Maps and International Specification for Sprint Orienteering Maps of International Orienteering Federation (IOF).

There also is a definition of "107 Earth wall" and "108 Small earth wall" in International Specification for Orienteering Maps and International Specification for Sprint Orienteering Maps and International Specification for MTB Orienteering Maps of International Orienteering Federation (IOF).

Examples

I have identified the following types of smaller peaks interesting to have in OSM:

  1. Sledding (playground=sledding) - typical knoll/hillock, to use rather with "man_made=peak"
  2. Landfill (landuse=landfill) - to use rather with "man_made=peak" and marked as an area, since they are frequently flat on their top (examples: [1], [2])
  3. Peaks in the park or in the housing estate - should be tagged as knoll/hillock, probably also used with "man_made=peak" (examples: [3], [4], [5])
  4. Mounds - probably should be always used with "man_made=peak"
  5. Natural hills - of course they exist too, but currently on OSM we can't distinguish them from mountain peaks, even if the difference is clearly visible; to be used with current "natural=peak"

Note: this is the list of notable special cases to better illustrate the problem, but they don't make the whole picture.

Tagging

New tags proposed here:

  • peak=mountain
  • peak=hill
  • peak=knoll/hillock
  • man_made=peak

All the tags associated with current natural=peak (like "name", "ele" and "wikipedia") can be used with no modification, however the new "height" tag may be useful for indicating relative height instead of (or parallell to) absolute elevation.

Hill tags natural=hill and a lot less common peak=hill are already used in the wild.

Applies to

This proposition applies mainly to nodes, but areas are also of interest here, since some hills have flat surface on top (like landfills).

Rendering

Rendering is important part of this enhancements, since we have to remember the scale. The symbol used up to this moment for peaks (Peak mapnik.png) may be visible for all the peak types, but with proper zooming. I propose rough zooming scheme to be like this:

  • mountain - from zoom level 11-13-14 (symbol - symbol+name - symbol+name+elevation/height)
  • hill - from 13-15-16
  • knoll/hillock - from 15-17-18

Default "*=peak" should be treated as "*=peak"+"peak=mountain", because we already have a lot of mountain peaks and they are the most important.

Optionally, for hills and knolls/hillocks we can render the triangle as brown (darker than orange) to better show the distinction between them and mountain peaks. Probably this would be a nice indicator when the height is known/important but we have no data/interest in elevation. If we have both the elevation and height, the standard orange can be used instead.

Features/Pages affected

Maybe also:

Comments

All the comments for this proposition should be written and discussed on the talk page.

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