Talk:Topographic prominence

Prime factor
I removed the claim in the lead that this is called "prime factor" in, um "Europe" (what language is "Europe"?) It seems that the Norwegian for "prominence" is primærfaktor, and this has made its way onto at least one page in Norwegian english. Trouble is that when he says "primary factor is a well known term among mountain enthusiasts", he means the obvious corresponding sentence in Norwegian (which I could read, but can't write). Unless there is evidence of this term actually being used in English, I don't think it belongs, even if anyone could decide whether primærfaktor is "prime" or "primary". Imaginatorium (talk) 15:20, 9 March 2016 (UTC)

Prominence Parentage
Prominence parentage appears to have become the established parentage standard on Wikipedia. I have clarified the definition of Topographic prominence to remove a tag, but I am concerned about the tagging of prominence related articles in general, which could threaten the whole future of Wikipedia's coverage of prominence. The definition given for prominence parentage states: The (prominence) parent peak of peak A can be found by dividing the island or region in question into territories, by tracing the two hydrographic runoffs, one in each direction, downwards from the key col of every peak that is more prominent than peak A. The parent is the peak whose territory peak A is in. This seems to me to be a clear, correct and definitive definition, but I cannot source this anywhere on the web, and unless this becomes sourceable, or is replaced by a sourced definition, there is a risk that someone may delete the prominence parentage section, which would threaten our coverage of topographic prominence in general. Viewfinder (talk) 16:56, 28 October 2016 (UTC)

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More definitions problems - possibly related to 'equivalence of definitions'
The reason I first came to the talk page was to comment on the paragraph at the beginning of the 'definitions' section: a 'please clarify' tag has been added to the statement that Everest's prominence is equal to its elevation, but the answer to the question ("why?") is right there at the beginning of that sentence - "by convention", which is a perfectly satisfactory answer.

Perhaps, though, the "why?" shouldn't be / isn't asking about why Everest's prominence equals its elevation, but why the answer to this question is given as "by convention" when, going by the first definition ("the height of the peak’s summit above the lowest contour line encircling it but containing no higher summit within it" at time of writing), one obtains precisely the elevation of Everest as its prominence, assuming sea level is the lowest contour line applicable to the definition i.e. assuming wet prominence is to be calculated, because this contour circumscribes no summit higher than Everest.

However, as far as the other two definitions are concerned as they are currently formulated ("the minimum height necessary to descend to get from the summit to any higher terrain" and, "for every path connecting the peak to higher terrain, find the lowest point on the path; the key col is defined as the highest of all such points; prominence is the difference between the elevation of the peak and the elevation of the key col," respectively [I have reworded for brevity but without reformulating]), the prominence of Everest can't be defined, in the first case because it is impossible to get from the summit of Everest to any higher terrain, and similarly in the second case because there are no paths connecting the peak of Everest to any higher terrain; thus, with either the second or the third definition of prominence, a convention regarding Everest is indeed required. This may be the reason for the qualifier "apart from this special case" before the claim that the definitions are equivalent, though it seems to me that there must be a better way of wording the section - something like giving definition one, stating Everest's prominence by this definition, then stating that for other peaks it can also be calculated in the other way(s). Maybe that just wouldn't read as well, but it would certainly remove the need for clarification, if there is one currently.

I read through the whole talk page to check this hadn't already been discussed, and enjoyed reading it despite not having read the whole article itself. I was particularly interested in the 'equivalence of definitions' section, although it was made harder to follow by the fact that the 'definitions' section in the article had clearly been edited since it was discussed, which is why I included the quoted or paraphrased definitions as they currently are in my comment above. It seems though that for the counterexample given, the first definition (at least the one that's first now) gives a different value from the second/third definition - so this is still or again a problem, four-and-a-half years later.

Furthermore, I realised after going back to the article that the wording (but not the formulation, as far as I can see) of the third definition contains an inconsistency in the first two sentences, "For every ridge (or path of any kind) connecting the peak to higher terrain, find the lowest point on the ridge. This will be at a col (also called a saddle point or pass)." On a path of some kind other than a ridge, the lowest point need not be a saddle point in the geometric sense, however the key col, defined to be the highest of all points that are the lowest point on some path connecting the summit with higher ground, will necessarily be a col and a saddle.

One resolution to this is to simply remove "(or a path of any kind)", however as a mathematician I feel better about using the "any path" version as it avoids any possible subjectivity in the definition of a 'ridge' and is otherwise equivalent. So instead I propose the definition read something more like, "For every path connecting the peak to higher terrain, find the lowest point on the path. The key col (or key saddle, or linking col, or link) is defined as the highest of these points, along all connecting paths. The prominence is the difference between the elevation of the peak and the elevation of the key col. See Figure 1." The example, "If the peak is the highest point on a landmass, the key col will be the ocean, and the prominence of the peak is equal to its elevation," still does not apply to Everest by this definition, as explained above; it could be kept in the definition with the qualifier, "but higher points exist on other landmasses," though of course it's still only an example since it's evident from the definition of the key col without being explicitly stated; if we were to leave it as it is it sounds more like a stated convention than an example, in which case it would (require a source, and also) apply to Everest, answering the 'why?' question I was commenting on above.

Lastly - sorry for the long post - the second and third definitions at time of writing are equivalent in a much stronger sense than that they always give the same result: the third definition is effectively a method of calculating the prominence by the second definition, as far as I can see. In other words, they are not so much equivalent definitions as a single definition restated, if one were to make such a distinction. I might argue that they need not 'both' be given here, unless some comparison of them is notable in the literature on topographical prominence, or unless I've misinterpreted that second one. Just some thoughts.

P.S. If the sentence "Together with the convention for Mount Everest, this implies that the prominence of any island or continental highpoint is equal to its elevation above sea level," which applies to the second/third definition, were to be reworded as something more like, "This implies that the prominence of any island or continental highpoint except the world's highest, Mount Everest, is equal to its elevation above sea level, hence a convention that the prominence of Mount Everest is also defined to be equal to its elevation above sea level," then this too answers the above question and removes any need for clarification, and therefore whichever sounds better of this, the "If the peak is the highest point on a landmass but higher points exist on other landmasses, the key col will be the ocean, and the prominence of the peak is equal to its elevation, hence a convention that the prominence of Mount Everest is also defined to be equal to its elevation above sea level," or some combination of the two, it would also remove the need to rearrange the section as I initially suggested, and maybe instead would only require a statement like, "Note that by [the first definition], the prominence of Everest can be calculated and can be shown indeed to equal its elevation." Adam Dent (talk) 10:58, 15 February 2018 (UTC)


 * To summarise, may I suggest that the section 'Definitions' be changed to the following:

There are at least two (related) definitions of prominence:


 * The prominence of a peak is the minimum height necessary to descend to get from the summit to any higher terrain, which can be calculated for a given peak in the following way: for every path connecting the peak to higher terrain, find the lowest point on the path; the key col (or key saddle, or linking col, or link) is defined as the highest of these points, along all connecting paths; the prominence is the difference between the elevation of the peak and the elevation of the key col. See Figure 1. (This implies that the key col of any island or continental highpoint where a higher point exists on another landmass (that is, all except Mount Everest, the Earth's highest mountain) will be the ocean, so the prominence of the peak is equal to its elevation above sea level, hence a convention that the prominence of Mount Everest is also defined to be equal to its elevation above sea level.)
 * The prominence of a peak is the height of the peak’s summit above the lowest contour line encircling it but containing no higher summit within it. Note that by this definition, the prominence of Everest can be calculated, and does indeed equal its elevation (thus, using this definition, no convention regarding Everest is required.) Adam Dent (talk) 11:17, 15 February 2018 (UTC)

How to calculate the prominence of Datuzi Peak?
Peakbagger listes a peak lower to be the parent of Datuzi Peak. What about, say, if we have a peak inside a crater which is taller than the crater? --146.95.196.222 (talk) 00:39, 22 August 2019 (UTC)
 * I think Peakbagger is just confused. Obviously the parent peak has to be higher, by any definition. Imaginatorium (talk) 03:01, 22 August 2019 (UTC)
 * Thank you! I still have something confused about the definition: suppose the Wizard Island Peak is taller than Mount Scott (or at least the Hillman Peak), how should we calculate its prominence? Any approach to it must pass through the Phantom Ship Overlook then. --146.95.196.129 (talk) 23:54, 22 August 2019 (UTC)
 * Sorry, I'm not familiar with the various places you mention. The prominence of the Wizard island peak is obviously the height above the surrounding lake. If that level varies a lot, then, well, the prominence varies. What is the problem with the other mountains? Imaginatorium (talk) 02:52, 23 August 2019 (UTC)

Example
I just created and uploaded this real-life example. Might be useful. --Kreuzschnabel (talk) 10:06, 7 October 2019 (UTC)

Confusing defition in the lead
Hello! I found the defition of "key col" provided in the lead ("the highest gap between two mountains") confusing and potentially misleading, so I changed it to "the highest col surrounding a peak". I also moved the hyperlink from the "col" part of the compound word "key col" to the mention of "col" in the parenthesis. Nikolaj1905 (talk) 12:16, 9 March 2020 (UTC)

Prominence parent
I can't make heads or tails of the defintion of prominence parent. The article says "The (prominence) parent peak of peak A can be found by dividing the island or region in question into territories, by tracing the two hydrographic runoffs, one in each direction, downwards from the key col of every peak that is more prominent than peak A." First of all, what is hydrographic runoff? I can not find a definition of it. Secondly, if I understand correctly the highest peak of all has no key col, but it will be a peak that is more promiment than A. So how do we apply the procedure to it? I think my confusion reflects a problem with the article, which is why I raise it here. MathHisSci (talk) 22:30, 6 May 2020 (UTC)
 * I think you are right, that the definitions are nothing as clear as they appear. Very roughly, the "hydrographic" thing means that the parent peak is the highest one you can get to by climbing from the key col if you never cross rivers. I can't imagine why this would be called "prominence parent", which seems to be completely meaningless. Imaginatorium (talk) 01:27, 25 August 2020 (UTC)

Parent peak
It currently says that the parent peak of the highest point of a landmass is either undefined (which I can understand) or is automatically defined to be Mt Everest, but that doesn't make any sense to me. For example, using the encirclement parentage criteria, the parent peak of Mount Kosciuszko (highest point in Australia) would be Puncak Jaya (highest point in New Guinea), not Mt Everest, and that would also be valid for a whole lot of island peaks. If there is some kind of convention which says we don't follow this criteria and just put Mt Everest by default, we need a source --Ngfsmg (talk) 01:16, 25 August 2020 (UTC)


 * (Sorry, I did not realise that this was your comment, so I am merging my comment into this section.)
 * The section "Parent Peak" is marked as unsourced, but since it consists mostly of logical argument about obvious facts, it is easy to check whether it is nonsense or not. User:Ngfsmg removed a reference to the ambiguity about peaks on separate landmasses (walandters, land surrounded by water), claiming it may not even be true. But its truth is exemplified by the current article which in one place asserts that Everest is the parent peak of Aconcagua, and in another asserts that Aconcagua has no parent. Of course it would be nice to have references to possible alternative definitions of all of these terms. Imaginatorium (talk) 01:23, 25 August 2020 (UTC)
 * But Mt Everest would be the parent peak to Aconcagua using the encirclement criteria, it just isn't like that for every peak --Ngfsmg (talk) 01:27, 25 August 2020 (UTC)
 * Um, no. You are using some kind of "it had better be close" intuition, which is not part of the definition. Of course with the exception of the ocean, key cols do not normally allow you to climb back up to a variety of peaks, but the ocean does: this means that the "other contour" encircles the rest of the world outside Australia. You would need to provide some reason for choosing New Guinea, rather than America, for example. Imaginatorium (talk) 01:44, 25 August 2020 (UTC)

It has nothing to do with being close or not, I already said it's due to the encirclement principle. They even talk about that in the dry prominence section--Ngfsmg (talk) 01:53, 15 September 2020 (UTC)

Wording
"The prominence of a peak may be defined as the minimum height necessary to descend to get from the summit to any higher terrain". The way this is worded made such a simple, intuitive concept so confusing for me. How could you descend to a higher elevation? I had to read other sources to figure out what this meant, which is that it is referring to a descent to the col to reach a different terrain that is higher relative to the position from that col. If instead, higher terrain is meant to be relative to the summit, then I still find that confusing because doesn't that imply that by definition, prominence only applies when there are other taller mountains? In any case, the sequence from descent to the higher terrain should not be contracted like this as though descent and ascent are simultaneous actions. I think there should be a way to rephrase this in a way that is both more concise and clearer and doesn't sound contradictory even if other people would not be as confused as I was. Sol Pacificus (talk) 20:28, 17 March 2021 (UTC)

Parent appears to have two definitions
It appears to me that the way parent peaks are defined in the definition, the true parent peak of anything is always going to be the next higher peak *anywhere in the world regardless of anything*. And that the *method* given for finding a parent will usually give some kind of "unofficial local parent" that will not likely be the true parent according to the definition. TooManyFingers (talk) 20:27, 10 September 2021 (UTC)

Mount Everest's dry prominence
This article claims that Mount Everest uses a different definition of dry prominence than every other mountain in the world. Other mountains measure their dry prominence in comparison to the lowest contour line that encircles the mountain but contains no higher summit. But the article claims that Mount Everest's dry prominence is measured in comparison to the deepest point on Earth: the Challenger Deep.

But that doesn't seem right to me, since the Challenger Deep doesn't encircle Mount Everest. It's only on the east side of it. That claim was added in one of Buaidh edits way back on 29 April 2008. It was a big edit, which added a lot of good information other than the part about Mount Everest.

https://www.floodmap.net/ shows that the lowest contour line that encircles Afro-Eurasia (but not the Americas) is 43 m below sea level. At 44 meters below sea level, you hit land in the Bering Strait. It also shows that the lowest contour line that encircles both Afro-Eurasia and the Americas is 800 m below sea level. At 801 meters below sea level, you hit land just north of the UK.

Comments? - 68.207.248.89 (talk) 05:49, 13 November 2021 (UTC)


 * Yes. I agree. The “convention” cited at that point smacks of gerrymandering. And it’s only one book.  In fact the whole unsourced section on calculation and also  “_in mountaineering_” looks erroneous to me,. In mountaineering, prominence is how far up you have to go from a col. The piece about k2 and  Everest south summit sums it up perfectly.
 * surely Mauna Kea could use challenger deep as well? It’s in the pacific. I’ll have a look for other citations, but if unfound I think we can safely change Everest s dry prominence to elevation +43 m
 * Jabberwoch (talk) 06:46, 16 November 2023 (UTC)
 * You just made an attempt to tidy this up, and referred to talk -- I suppose you mean this topic?
 * Actually I think that topologically speaking, the surface of the earth is a sphere (or is it the surface of a sphere, well...) and if you start from any contour line around Mt Everest, and expand it to surround more and more of the earth's surface at a lower and lower contour, then nothing special happens when the contour reaches the "col" in the Bering strait - it's just that the contour now includes all of N and S America (and perhaps a huge chunk more). As you keep expanding this contour line, the enclosed area keeps growing, but at some point you realise you have included more than half of the earth's surface, and seen from the "other side" as it were, the contour is actually shrinking, until eventually it includes everwhere on the earth's surface except a bit of the Challenger deep. From above, the "prominence of a peak is the minimum height necessary to descend to get from the summit to any higher terrain", but this will never happen when you start from Everest, because there is no higher peak, and it is totally arbitrary to think of the second most prominent peak (Aconcagua) as somehow an ersatz "higher peak". So therefore, I think the valid claims are: either "Everest just has no prominence" or "Challenger deep". Imaginatorium (talk) 11:35, 14 June 2024 (UTC)

"America First"
"... in US English, and. drop or relative height in British English".

That so-called US English (American) takes precedence over (so-called) British English (English) has more than a hint of irony about it and epitomises the Trumpian "America First" outlook in Wikipedia. It's like 'Chinese American' taking precedence over 'American'. I wonder how Americans would feel about that?

86.191.214.39 (talk) 04:22, 28 November 2023 (UTC)

Only referring to peak vs. col or saddle?!
What's then the term for height difference for any height or point on its slope vs the plain surrounding it? I believe it's also prominence, which makes this article particlularist, one-sided, and therefore misleading. Am I wrong? If so: what is then the more general term?

One example from Britannica: "The highest crest of the main range of the western Kunlun Mountains is Mount Keriya, at an elevation of 23,359 feet (7,120 metres). ... The surrounding plain lies above 16,000 feet (4,900 metres); hence, these mountains do not have the prominence of other high mountains in Asia." It does refer to peaks (also in sentence I cut out), but then comparing their altitude to the surrounding plain's, NOT to each other or the saddles between them.

Geographers? English native-speakers? Thank you. Arminden (talk) 11:51, 30 March 2024 (UTC)

Two totally different concepts that should be split into two articles
Reading this article I get the feeling that two totally different concepts have been merged into one. The article makes sense (although things could be simplified) as long as it talks about the relative height of a peak/mountain, i.e. measuring its height from its foot to the summit, instead of giving its height from sea level.

However, when the concepts "prominence parent"/"parent peak" and "wet" versus "dry" prominence are introduced, the article jumps from the concept of relative height to some system of height measuring on a global scale, where Mount Blanc in the European Alps and the lone peak of Kilimanjaro in East Africa both have Mount Everest in the far away Himalayas as "parent peak", as they all belong to the landmass Afro-Eurasia – and Mount Everest's "dry prominence" is suddenly measured in comparison to the Challenger Deep in the Pacific.

I would suggest splitting this article in two:

One about a mountain's height from its foot or a peak's height from the nearest col, e.i. its visual height and the practical height for climbers> This is also how [[List of the most prominent summits of the United States}} and several articles define topographic prominence. If there should be any mentioning of "parent peak" in that article, it should refer to the highest peak in the mountain range that the mountain in question is part of.

The other article would deal with heigh measurements on a global scale from a cartographic perspective. That's especially where the concept of "dry prominence" belongs.

The concepts of "key col" and "parent peak" are especially confusing, where the article intro simply says that these are "selected according to various criteria". Both concepts seem to come from a single source, a web site by programmer Andrew Kirmse. He and his co-author Jonathan de Ferranti did some impressive research that was published in the Sage Journal Progress in Physical Geography in 2017, but are its conclusions universally accepted by geography experts? Thomas Blomberg (talk) 11:53, 7 April 2024 (UTC)


 * Hi . I'm happy you brought it up. Have you read the question I've raised, one above this one? I need a widely accepted term for the height difference for a hill- or mountaintop, or any point on the slope below, vs the plain surrounding it. Relative prominence? What's the dry prominence you brought up? Is there a standard terminology used all across the English-speaking geographers' guild? We need to be able to wikilink terms used in various articles to a thoroughly worked-through one here.
 * Only once the terminology is figured out can we start splitting up - or not - the article. Why not keep it all under "topographic prominence" once different, clearly defined sections are set up?
 * In principle, we need agreed-upon terms for the height difference between a positive height, either representing a peak or not, in relation to
 * the peak's own col
 * maybe its saddle, too
 * the main plateau or plain at the foot of the height
 * the main peak in the range
 * sea level
 * sea bottom
 * what else? The next tall underwater peak?
 * I see there's a whole series of terms. Having a section (a glossary?) defining each of them is a mandatory first step here, as it is anywhere. Then each of the main terms should get its own section.
 * prominence
 * relative prominence
 * wet prominence
 * dry prominence
 * prominence parent
 * parent peak
 * key col
 * I'm sure there are more.
 * What do you think? Arminden (talk) 12:59, 7 April 2024 (UTC)
 * I agree totally. Yes, I did read your question, which illustrates the same problem. From what I understand, "topographic prominence" is a term used by some experts for the height of a mountain from its foot (i.e. the lowest contour line encircling it) to its peak, also known as "relative height" as opposed to absolute height (i.e. height above mean sea level).
 * So far, so good, but in the section "Definition", things start to be confusing when the writers try to define the term "key col" and gets into an awful muddle, which ends with the statement that "Mount Everest's prominence is defined by convention as its height, making it consistent with prominence of the highest peaks on other landmasses", adding that "an alternative equivalent definition is that the prominence is the height of the peak's summit above the lowest contour line encircling it, but containing no higher summit within it" – which is what the picture next to the section "In mountaineering" exemplifies very well.
 * The section "Illustration" mentions "parent peak" for the first time and makes the rather outlandish claim that Mount Everest's peak is the parent peak of Aconcagua in Argentina, the world's second highest mountain. The only way to achieve this is to draw contour lines across the whole globe, including the ocean bottoms.
 * The section "Parent peak" confuses things even further, introducing four different ways to calculate parentage, all of them apparently valid. The first one, "encirclement or island parentage", claims that Mont Blanc in the Alps has Mount Everest in the Himalayas as "parent peak". How come? Well, both mountain ridges are on the Afro-Eurasian landmass and when checking all the contour lines on that landmass, two 113 m contour lines meet near Lake Onega, northwest of St Petersburg. One of those can supposedly be traced back to the Alps and the other to the Himalayas. However, they are separate, so that line can't be the "key col", and the definition of key col in the Col article clearly puts the key col close to the mountain in question. In my mind, the term "parent peak" should be restricted to a mountain ridge.
 * Further down in the article, the terms "wet" and "dry" are introduced, stating that most of the previous text refers to "wet" prominence, which limits measurements to the area of dry land surrounding a mountain, so the author of that section wants to widen the measurements to a global scale instead, where water masses are disregarded and we get a chance to measure a mountain peak from the deepest spot on earth, i.e. the Challenger Deep, which means that Mount Everest is 19,759 metres heigh instead of the established 8,848 meters from sea level. But why other mountains in the "dry" list aren't also measured from the Challenger Deep isn't explained. There is also no explanation why Mount Everest's "topographic prominence" isn't measured from the South Col or the North Col, where climbers start out when trying to conquer the highest peak in the world.
 * Looking back into the revision history of the article, it has changed drastically over the years. What started out as an article just defining prominence as the height from the foot of a mountain or the height from the nearest valley within a mountain ridge, has since 2004 evolved into a very long and complex article about key cols, parent peaks and dry prominence, which has nothing to do with the original purpose: to explain why height above sea level doesn't necessarily reflect the height on the mountain itself - and definitely not the height that any climbers will have to conquer.
 * This is why I think this article should be split into two: one that deals with what the first sentence says: "In topography, prominence (also referred to as autonomous height, relative height, and shoulder drop in US English, and drop or relative height in British English) measures the height of a mountain or hill's summit relative to the lowest contour line encircling it but containing no higher summit within it", and another which deals with things like the different systems of determining parent peaks och the concept of "dry prominence", where suddenly underwater mountains become interesting and every mountain in the world theoretically could be made 10,920 metres higher by measuring them from the bottom of the Challenger Deep.
 * However, I was just passing by and made a layman's observation, so I leave that job and that discussion to the editors who have spent so much time putting this article together. Thomas Blomberg (talk) 16:36, 9 April 2024 (UTC)

This is a pointless concept.
As presented in this article, the concept of prominence is meaningless and pointless.

I would have thought the concept of prominence would be to indicate how high a mountain is in relation to the surrounding terrain, as in, how prominent is this peak?

i.e. If I were to climb Mt. Everest, and wanted to know how 'big' the mountain is, this article says it has a prominence of 8,849m, which means I'm starting my climb from somewhere in the Bay of Bengal. However, the 'base' of Mt Everest is around 4200m(depending where measured), meaning the 'how big is this mountain?'/prominence is around 4400m.

As a result I'm left with not the faintest clue about how big Mt Everest is, because I know it sits on a mountain range and doesn't rise to 8,849m from near sea level, like a giant volcanic cone rising out of the ocean.

It's meaningless and thus pointless. 61.68.160.116 (talk) 23:19, 17 April 2024 (UTC)


 * You may be interested to know that in 1990, Tim Macartney-Snape became the first person to walk and climb from sea level to the top of Mount Everest. HiLo48 (talk) 00:30, 18 April 2024 (UTC)