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"Prominence" redirects here. For other uses, see Prominence (disambiguation). The term prominence can refer to Solar prominence, a phenomenon occurring on the Sun Topographic prominence, a categorization of hills

In topography, prominence, also known as autonomous height, relative height or shoulder drop (in North America) or prime factor (in Europe), is a concept used in the categorization of hills and mountains, also known as peaks. Topography ( topo-, "place" and graphia, "writing" is the study of Earth 's Surface features or those of Planets A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak It is a measure of the independent stature of a summit. In topography a summit is a point on a surface which is higher in Elevation than all points immediately adjacent to

Contents

Definition of prominence

There are several equivalent definitions, which are satisfactory for all but Mount Everest:

Figure 1. Vertical arrows show the topographic prominence of three peaks on an island. A dotted horizontal line links each peak (except the highest) to its key col
Figure 1. Vertical arrows show the topographic prominence of three peaks on an island. An island (ˈaɪlənd or isle (/ˈaɪl/ is any piece of land that is completely surrounded by water in two dimensions above high tide and isolated from other significant A dotted horizontal line links each peak (except the highest) to its key col

Prominence in mountaineering

Prominence is interesting to some mountaineers because it is an objective measurement that is strongly correlated with the subjective significance of a summit. “Alpinist” redirects here See also Alpinist (magazine Mountaineering is the Sport, Hobby or Profession of Peaks with low prominences are either subsidiary tops of some higher summit or relatively insignificant independent summits. Peaks with high prominences tend to be the highest points around and are likely to have extraordinary views.

For example, the world's second highest mountain is K2 (height 8,611 m, prominence 4,017 m) rather than Mount Everest's South Summit (height 8,749 m, prominence about 10 m), a subsummit of the main summit, since only summits with a sufficient degree of prominence are regarded as independent mountains. K2 is the second- highest Mountain on Earth (after Mount Everest) Mount Everest, also called Sagarmatha (सगरमाथा meaning Head of the Sky) or Chomolungma, Qomolangma or Zhumulangma (in

Many lists of mountains take topographic prominence as a criterion for inclusion, or cutoff. The following is a list of the world's 100+ highest mountains per height Above sea level, all of which are located in Asia John and Anne Nuttall's The Mountains of England and Wales uses a cutoff of 15 m (about 50 ft), and Alan Dawson's list of Marilyns uses 150 m (about 500 ft). A Marilyn is a type of Mountain or Hill in Great Britain, Ireland or surrounding islands with a relative height of at least 150 metres (Dawson's list and the term "Marilyn" are limited to the British Isles. ) In the contiguous United States, the famous list of "fourteeners" (14,000 foot / 4268 m peaks) uses a cutoff of 300 ft / 91 m (with some exceptions). Qualification criteria Not all summits over 14000 feet qualify as fourteeners Also in the U. S. , 2000 feet (610 m) of prominence has become an informal threshold that signifies that a peak has major stature. Lists with a high topographic prominence cutoff tend to favour isolated peaks or those that are the highest point of their massif; a low value, such as the Nuttalls', results in a list with many summits that may be viewed by some as insignificant. In Geology, a massif is a section of a planet's crust that is demarcated by faults or Flexures In the movement of the crust, a massif

While the use of prominence as a cutoff to form a list of peaks ranked by elevation is standard, and is the most common use of the concept, it is also possible to use prominence as a mountain measure in itself. This generates lists of peaks ranked by prominence, which are qualitatively different from lists ranked by elevation. This is a list of Mountain peaks ordered by their Topographic prominence. Such lists tend to emphasize isolated high peaks, such as range or island high points and stratovolcanoes. A stratovolcano, also called a composite volcano is a tall conical Volcano composed of many layers of hardened Lava, Tephra, and Volcanic One advantage of a prominence-ranked list is that it needs no cutoff, since a peak with high prominence is automatically an independent peak.

Parent peak

It is common to define a peak's parent as a particular peak in the higher terrain connected to the peak by the key col. If there are several higher peaks there are various ways of defining which one is the parent. These concepts give ways of putting all peaks on a landmass into a hierarchy, showing which peaks are subpeaks of which others. For example, in Figure 1, the middle peak is a subpeak of the right peak, which is in turn a subpeak of the left peak, which is the highest point on its landmass. In that example, there is no controversy over the hierarchy; in practice, there are different definitions of parent. These different definitions follow.

(A special case occurs for the highest point on an oceanic island or continent. Some sources define no parent in this case; others treat Mount Everest as the parent of every such peak (with the ocean as the "key col"). )

Encirclement or island parentage

Also called prominence island parentage, this is the most mathematically natural definition, and is defined as follows. The key col of peak A is at the meeting place of two closed contours, one encircling A and the other containing at least one higher peak. The encirclement parent of A is the highest peak that is inside this other contour. In terms of the rising-sea model, the two contours together bound an island, with two pieces connected by an isthmus at the key col. The encirclement parent is the highest point on this entire island.

For example, the encirclement parent of Mont Blanc, the highest peak in the Alps, is Mount Everest. Mont Blanc Massif The Mont Blanc ( French for white mountain) or Monte Bianco ( Italian 'White Mountain' also Mount Everest, also called Sagarmatha (सगरमाथा meaning Head of the Sky) or Chomolungma, Qomolangma or Zhumulangma (in Mont Blanc's key col is a piece of low ground near Lake Onega in northwestern Russia (at 113 m elevation), on the divide between lands draining into the Baltic and Caspian Seas. Lake Onega (also known as Onego, Онежское озеро Onezhskoe ozero, i A drainage divide, water divide, divide or (outside North America) watershed is the line separating neighbouring Drainage basins The Baltic Sea is a Brackish inland sea located in Northern Europe, from 53°N to 66°N Latitude and from 20°E to 26°E Longitude. The Caspian Sea is the largest enclosed body of water on Earth by area variously classed as the world's largest lake or a full-fledged Sea. This is the meeting place of two 113 m contours, one of them encircling Mont Blanc; the other contour encircles Mount Everest. This example demonstrates that the encirclement parent can be very far away from the peak in question when the key col is low.

This means that, while simple to define, the encirclement parent often does not satisfy the intuitive requirement that the parent peak should be close to the child peak. For example, one common use of the concept of parent is to make clear the location of a peak. If we say that Peak A has Mont Blanc for a parent, we would expect to find Peak A somewhere close to Mont Blanc. This is not always the case for the various concepts of parent, and is least likely to be the case for encirclement parentage.

The encirclement parent is the highest possible parent for a peak; all other definitions pick out a (possibly different) peak on the combined island, a "closer" peak than the encirclement parent (if there is one), which is still "better" than the peak in question. The differences lie in what criteria are used to define "closer" and "better. "

Prominence parentage

The (prominence) parent peak of peak A can be found by dividing the island or region in question into territories, by tracing the runoff 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.

Prominence parentage can also be defined in the following way. The parent peak of peak A is found by continuing along a ridgeline from the key col; the nearest peak to A found in such a manner that has a higher topographic prominence than A is the prominence parent.

For hills with low prominence in Britain, a definition of 'parent Marilyn' is sometimes used to classify low hills. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located A Marilyn is a type of Mountain or Hill in Great Britain, Ireland or surrounding islands with a relative height of at least 150 metres This is found by dividing the region of Britain in question into territories, one for each Marilyn. Once again, the parent Marilyn is the Marilyn whose territory the peak is in. Obviously, if a peak is the highest point of its island, it has no parent. Likewise, if a hill is on an island (in Britain) whose highest point is less than 150m, it has no parent Marilyn.

Prominence parentage is the only definition used in the British Isles because 'encirclement' parents break down when the key col approaches sea level. The British Isles (Irish variously Na hOileáin Bhriotanacha, Oileáin Iarthair Eorpa, Éire agus an Bhreatain Mhór; Ellanyn Goaldagh Eileanan Using this definition, the parent of any low-lying bump next to the sea would be Ben Nevis - which could be said to be irrelevant and confusing. Similarly 'height' parentage is not used because there is no obvious standard for what the cutoff used should be.

Normally it will suffice to find the nearest higher and more prominent neighbour. However, some regions are topographically awkward.

This might seem arbitrary, but it gives a clear and unambiguous definition for the 'parent' of a mountain that is more significant than, connected to and reasonably close to it. It also enables one to make a 'hierarchy' of peaks going back to the highest point on the island. One such chain in the British Isles would read;

Billinge Hill --> Winter Hill --> Hail Storm Hill --> Boulsworth Hill --> Kinder Scout --> Cross Fell --> Helvellyn --> Scafell Pike --> Snowdon --> Ben Nevis. Billinge Hill, or affectionately known by locals as Billinge Lump, or just simply The Lump is the highest point in the Metropolitan Borough of St Helens Hail Storm Hill, also known as Cowpe Moss, is the highest point of the Forest of Rossendale, an area of Moorland and Hill country situated Boulsworth Hill is a large expanse of Moorland, the highest point of the South Pennines of south-eastern Lancashire, separating the District of Kinder Scout is a Moorland Plateau (and Mountain) in the Dark Peak of the Derbyshire Peak District in the United At 893 m Cross Fell is the highest point in the Pennine Hills of Northern England. |} Helvellyn is a mountain in the English Lake District, the apex of the Eastern Fells. |} At 978 metres (3209 feet Scafell Pike is the highest mountain in England. For other meanings see Snowdon (disambiguation. Snowdon (Yr Wyddfa is the highest Mountain in Wales and the third Ben Nevis ( Gaelic: Beinn Nibheis, peˈɲivəʃ is the highest mountain in the British Isles.

At each stage in the chain both the height and prominence are increasing.

Height parentage

Height parentage is a less widely used term. It is similar to prominence parentage, but it requires some sort of prominence cutoff criterion. The height parent is the closest peak to peak A (along all ridges connected to A) that has a greater height than A, and is above the prominence cutoff. For example, Mont Blanc's height-parent is either a minor peak in the north-west Caucasus (if the prominence cutoff is low), or Mount Elbrus (if the cutoff is high). Mont Blanc Massif The Mont Blanc ( French for white mountain) or Monte Bianco ( Italian 'White Mountain' also The Caucasus ( also referred to as North Caucasus) is a geopolitical region located between Europe Asia & Middle East Mount Elbrus (Эльбрус is a Mountain located in the western Caucasus Mountain range, in Kabardino-Balkaria and Karachay-Cherkessia

The disadvantage of this concept is that it goes against the intuition that a parent peak should always be more significant than its child. However it can be used to build an entire lineage for a peak which contains a great deal of information about the peak's position.

Other criteria

To choose among possible parents, instead of choosing the closest possible parent, it is possible to choose the one which requires the least descent along the ridge.

In general, the analysis of parents and lineages is intimately linked to studying the topology of watersheds. Topology ( Greek topos, "place" and logos, "study" is the branch of Mathematics that studies the properties of A drainage divide, water divide, divide or (outside North America) watershed is the line separating neighbouring Drainage basins Further discussion of parents can be found in the Orometry article at peaklist.org.

Interesting prominence situations

The key col and parent peak are often close to the subpeak but this is not always the case, especially when the key col is relatively low. It is only with the advent of computer programs and geographical databases that thorough analysis has become possible.

While it is natural for Aconcagua to be the parent of Mount McKinley, since Mount McKinley is a major peak, consider the following situation: Peak A is a small hill on the coast of Alaska, with elevation 100 m and key col 50 m. Then the encirclement parent of Peak A is also Aconcagua, even though there will be many peaks closer to Peak A which are much higher and more prominent than Peak A (for example, Mount McKinley). This illustrates the disadvantage in using the encirclement parent.

Calculations and mathematics of prominence

When the key col for a peak is close to the peak itself, prominence is easily computed by hand using a topographic map. A topographic map is a type of Map characterized by large-scale detail and quantitative representation of relief, usually using Contour lines in modern However, when the key col is far away, or when one wants to calculate the prominence of many peaks at once, a computer is quite useful. Edward Earl has written a program called WinProm which can be used to make such calculations, based on a Digital Elevation Model. Edward Arthur Earl (born 1964 in Brooklyn) is an American computer scientist and an author of WinProm program WinProm is a Computer program written by a Mathematician Edward Earl of San Diego. A digital elevation model ( DEM) is a Digital representation of ground Surface Topography or Terrain. The underlying mathematical theory is called "Surface Network Modeling," and is closely related to Morse Theory. "Morse function" redirects here In another context a "Morse function" can also mean an Anharmonic oscillator.

A note about methodology: when using a topographic map to determine prominence, one often has to estimate the height of the key saddle (and sometimes, the height of the peak as well) based on the contour lines. A topographic map is a type of Map characterized by large-scale detail and quantitative representation of relief, usually using Contour lines in modern Assume for simplicity that only the saddle elevation is uncertain. There are three simple choices: the pessimistic, or clean prominence, assumes that the saddle is as high as it can be, i. e. its elevation is that of the higher contour line nearest the saddle. This gives a lower bound on the possible prominence of the peak. [2] Optimistic prominence assumes that the saddle is as low as possible, yielding an upper bound value for the prominence. Midrange or mean prominence uses the mean of these two values.

Which methodology is used depends on the person doing the calculation and on the use to which the prominence is put. For example, if one is making a list of all peaks with at least 2,000 ft (610 m) of prominence, one would usually use the optimistic prominence, to include all possible candidates (knowing that some of these could be dropped off the list by further, more accurate, measurements).

Wet prominence and dry prominence

There are actually two varieties of topographic prominence: wet prominence and dry prominence. [3] Wet prominence is the topographic prominence discussed in this article. Wet prominence assumes that the surface of the earth includes all permanent water, snow, and ice features. Thus, the wet prominence of the highest summit of an ocean island or landmass is always equal to the summit's elevation.

Dry prominence, on the other hand, ignores water, snow, and ice features and assumes that the surface of the earth is defined by the solid bottom of those features. The dry prominence of a summit is equal to the wet prominence of that summit unless the summit is the highest point of a landmass or island, or a summit surrounded by snow or ice. If a summit is completely surrounded by a water, snow, or ice feature, the dry prominence of that summit is equal to the wet prominence plus the depth of the highest col.

The dry prominence of Mount Everest is, by convention, equal to its wet prominence (8850 m) plus the depth of the deepest hydrologic feature (the Challenger Deep at 10,911 m), or 19,761 m. Mount Everest, also called Sagarmatha (सगरमाथा meaning Head of the Sky) or Chomolungma, Qomolangma or Zhumulangma (in The Challenger Deep is the deepest surveyed point in the oceans with a depth of about 11000 metres (about 36000 feet The dry prominence of Mauna Kea is equal to its wet prominence (4205 m) plus the depth of its highest col (about 5125 m), or about 9330 m; this is the world's largest dry prominence after Mount Everest. Mauna Kea is a Dormant volcano in the Hawaiian Islands, one of five volcanoes which together form the Island of Hawaii. [3] The dry prominence of Aconcagua is equal to its wet prominence (6962 m) plus the depth of the highest col of the Bering Strait (about 50 m), or about 7012 m. Cerro Aconcagua is the highest mountain in the Americas, and the highest mountain outside Asia. The Bering Strait (Берингов пролив Beringov proliv) is a sea Strait between Cape Dezhnev, Russia, the easternmost point (169°43'

Dry prominence is also useful for measuring submerged seamounts. A seamount is a Mountain rising from the Ocean Seafloor that does not reach to the water's surface ( Sea level) and thus is not an Island Submerged summits have both a dry topographic prominence and a topographic isolation. The topographic isolation of a summit is the minimum horizontal ( Great circle) distance to the nearest point of higher Elevation.

Debates about the use of prominence

The use of topographic prominence as a cutoff to eliminate subpeaks is well-established. This and the following sections address the merits and criticisms of using prominence as a primary mountain metric, for example, in creating lists of mountains ranked by prominence.

Merits

Criticism

The use of topographic prominence as a primary mountain metric has been widely criticised, for the following reasons.

References

  1. ^ a b The more common convention among the sources for prominence calculations is to ignore man-made alterations in the landscape, particularly for saddle heights. This convention is not universally agreed upon, and presents particular difficulties in the case of mountaintop removal. Mountaintop removal mining ( MTR) often referred to in the industry as mountaintop mining/valley fills (MTM/VF is a form of Surface mining that involves an However for high-prominence peaks (and for low-prominence subpeaks with intact summits), the difference in prominence values for the two conventions is typically relatively small.
  2. ^ This assumes that the map itself is accurate; inaccuracies in mapping lead to further uncertainties and a larger error bound.
  3. ^ a b Adam Helman, The Finest Peaks---Prominence and Other Mountain Measures, 2005.
  4. ^ Dawson, Alan (1992). The Relative Hills of Britain. Milnthorpe: Cicerone Press, p 253. ISBN 1-85284-068-4.  
  5. ^ This fails to be true in regions where no summit, or only the highest summits, are above tree line. The tree line or timberline is the edge of the habitat at which Trees are capable of growing

See also

External links

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