render natural=volcano different from natural=peak

[imagico]

I mean in general design, the color is already different.

Reason: natural=volcano is meant (see wiki) and is practically used for all kind of volcanic features and not just for volcanic mountain peaks:

http://www.openstreetmap.org/node/2281252654 http://www.openstreetmap.org/node/1764264178 http://www.openstreetmap.org/node/1366173854 http://www.openstreetmap.org/node/270951619

Implying a peak in rendering is also confusing for the mapper since it contradicts the idea of placing the node at the volcanic opening or the middle of the main caldera.

It probably makes sense to render natural=volcano as label only.

[geowOSM]

Full support - a volcano is a more or less extended geological body and the peak is almost never the central vent or fissure. Limitation to nodes (wiki) should be extended to areas.

[javbw]

The peaks may also be part of the full volcano. A common volcano caldera may have a single popular name, and the little peaks along it's Rim unknown little blips. but since we can't say "this is an unimportant little hill, render at z17 and below" - we can't relegate the little lumps to some sub-status of the caldera, since all "peaks" are equal. For some reason.

This was an issue I brought up in another discussion about gate renderings at zoom levels. https://github.com/gravitystorm/openstreetmap-carto/issues/323. Please look at the pictures imbedded in the post for the issues with labeling Mt Akagi and it's worthless little "peaks".

Quick! name the 7 or 8 tallest "peaks" in Japan! nobody knows their names! they are all 20m tall blips ringing the crater of Mt Fuji. http://garywolff.com/mt_fuji_trail_maps/ohachimeguri_trail_map.jpg

There has to be a solution for dealing with a volcanic caldera where the most interesting thing is the crater or vent area - and the little peaks don't really matter so much (I'm not talking "prominence" or technical terms - but based on physical size and cultural importance) - or the fact that a lump the size of a building and mount Everest get rendered and labeled at the same zoom levels.

[imagico]

There are two very different matters here - the principle problem of importance rating of point features - which in very similar ways applies to populated places (#1461), airports (#1143) and similar, and the problem of a very different definition of natural=peak and natural=volcano which disqualifies them from being rendered in a very similar styling. These two should be kept apart, this issue is about the latter.

[matkoniecz]

I think that it would be better to change wiki before rendering (currently it recommends using only nodes and it is not mentioned how peak of volcano should be mapped).

[imagico]

I added a clarifying note but except for the rendering section i see nothing on the natural=volcano wiki page that indicates any connection to natural=peak. The implication that natural=volcano implies a mountain peak comes from rendering practice.

If natural=volcano can also be mapped as an area is an unrelated question, which is mostly a matter of defining what the limit of a volcano is (which is tricky).

[kocio-pl]

For example this volcano tagged as an area is apparently not active. We could render area as natural=cliff in such cases and make it red for active ones, but it of course means more precise tagging and a database reload are needed.

Regarding to important/unimportant peaks in Japan (and elsewhere) - @javbw brought interesting point about our system:

Capturing local / regional information on what should and shouldn't be shown at certain zoom levels - importance - makes a better map.

Ignoring it seems to be the exact opposite of OSM's mission to capture local knowledge to make a superior map.

This is a tagging problem in the first place and rendering can only follow it, but it is a separate issue if it really will or we don't like to highlight anything just because it's "known".

[kocio-pl]

They are rendered different now.

[matthijsmelissen]

No, the issuevfrom the opening post is still present.

[kocio-pl]

I'm unable to dig deeper, but if you think I misunderstood this ticket, just reopen it please.

[matkoniecz]

I mean in general design, the color is already different.

[Tomasz-W]

A volcano is a kind of peak, so I don't see the need for rendering change. It's readable and intutive, I think.

[matkoniecz]

Reason: natural=volcano is meant (see wiki) and is practically used for all kind of volcanic features and not just for volcanic mountain peaks:

Quoted from the first post.

[jeisenbe]

@Tomasz-W would you be interested in designing a "volcanic vent" icon? I think this would be a very helpful change.

[imagico]

FYI - there are two different sized symbol for volcanoes in the ac-style: https://github.com/gravitystorm/openstreetmap-carto/commit/99e573814e7307aad20adbc123c3130f1cc85966