topic Re: How do I measure prominence? in ArcGIS Solutions Questions

How do I measure prominence?

MichaelThompson2 — Tue, 21 Apr 2015 18:58:17 GMT

Does anyone know if ArcMAP or any of the other ArcGIS programs can easily measure prominence? I searched around a bit and haven't come up with anything yet...

Thanks everyone!

Re: How do I measure prominence?

ChrisDonohue__GISP — Tue, 21 Apr 2015 20:40:35 GMT

Can you provide some context on what Prominence means in your case? Is it a defined process, equation, analysis, etc? How does one typically figure it out? Knowing this will help in finding possible GIS solutions to derive it.

Chris Donohue, GISP

Re: How do I measure prominence?

ChrisDonohue__GISP — Tue, 21 Apr 2015 20:50:03 GMT

Is your question related to "Topographic Prominence"?

Topographic prominence - Wikipedia, the free encyclopedia

If so, have you determined which specifications will be used to determine Prominence? It looks like there have historically been several different criteria used in determining a high points Prominence.

Chris Donohue, GISP

Re: How do I measure prominence?

MichaelThompson2 — Wed, 22 Apr 2015 14:57:19 GMT

Topographic prominence is exactly what I mean. I would like to be able to calculate the height of individual peaks in order to identify unique summits.

Thank you

Re: How do I measure prominence?

ChrisDonohue__GISP — Wed, 22 Apr 2015 19:03:31 GMT

This is an interesting concept. I don't know the exact answer, but poked around and someone has written a book on the subject of Prominence. Based on the excerpts of this book by Adam Helman posted online, there seems to be several flavors of Prominence and a variety of criteria that can be chosen for each:

https://books.google.com/books?id=kr8AM-w8IFQC&pg=PT165&lpg=PT165&dq=prominence+island+parentage&source=bl&ots=kuZc6R7K9…

Once a specific Prominence definition is chosen, it looks like it would be an interesting GIS challenge. For starters, you would need a Digital Elevation Model (DEM) of the complete extent of the project area, which would likely cover a vast area. For example, to derive the Prominence of Mount McKinley in Alaska, one typically would start with a DEM covering North, Central, and South America.

The general solution process appears to be identifying the highest point in your project area (Peak 1), then looking at the next highest (Peak 2) and finding the highest point of land (the col or saddle) that connects each. Then one checks the elevation distance between the col and Peak 2 to determine the Prominence of Peak 2, assuming the distance is more than your cutoff amount. For example, if you determine your cutoff will be "for a peak to be distinctive, it must be at least 500 feet higher than the surrounding terrain connecting other peaks", then the distance of less than the cutoff makes that peak invalid for consideration of having any Prominence. Then repeat a comparison of Peak 2 to Peak 3, then Peak 3 to 4, etc. Note that Peak 1 is a special situation - it does not normally get a Prominence, but if one is required it is typically its elevation compared to sea level.

An article in Wikipedia offers some hints at the analytical process:

Calculations and Mathematics:

When the key col for a peak is close to the peak itself, prominence is easily computed by hand using a topographic map. 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. The underlying mathematical theory is called "Surface Network Modeling," and is closely related to Morse Theory.

Topographic prominence - Wikipedia, the free encyclopedia

However, most of the links are dead.

Chris Donohue, GISP

Re: How do I measure prominence?

MichaelThompson2 — Mon, 04 May 2015 23:12:54 GMT

The method you describe to do this seems to be a good way to derive prominence values for peaks. It also seems like a lot of work! I think I will do some more digging on this topic because I doubt there is an existing tool within ArcMAP that can calculate these values easily, or at least with minimal input. I was hoping I could just give ArcMAP a DEM and push the "Go" button. It does not appear to be that easy.

Thank you for such a great explanation, Chris!

Re: How do I measure prominence?

ChrisDonohue__GISP — Mon, 04 May 2015 23:23:53 GMT

It's an interesting spatial challenge. I'm pretty sure it can be done in GIS, I'm just not sure which spatial processes could be used to resolve some parts of it.

I wonder if there is another area of GeoNet, or another forum out there that would be more likely trafficked with the folks who would know this particular specialty...

Chris Donohue, GISP

Re: How do I measure prominence?

SepheFox — Tue, 05 May 2015 02:55:18 GMT

I have been following this post with interest, and I think at this point it would help if Michael defined exactly the definition of prominence he is after.

I've been assuming he meant this definition, from wikipedia: "In topography, prominence characterizes the height of a mountain or hill's summit by the vertical distance between it and the lowest contour line encircling it and no higher summit. It is a measure of the independence of a summit."

Graham's reply, while creative, seems to be getting at prominence as the difference in height between the peak, and surrounding lower peaks, unless I'm misunderstanding it. I'm also confused by Chris's comment that a prominence analysis of Mt McKinley would require "a DEM covering North, Central, and South America". How so? By the WikiPedia definition, wouldn't it just require the area encompassing the surrounding peaks, and/or water features?

Re: How do I measure prominence?

ChrisDonohue__GISP — Tue, 05 May 2015 14:44:25 GMT

The McKinley/Denali example comes from the Wikipedia article under "Interesting prominence situations", and I agree it sounds weird at first read, though it does make sense:

The key col of Mount McKinley (also called Denali) in Alaska (6,194 m) is a 56 m col near Lake Nicaragua (unless one accepts the Panama Canal as a key col; this is a matter of contention). McKinley’s encirclement parent is Aconcagua (6,960 m), in Argentina, and its prominence is 6,138 m. To further illustrate the rising-sea model of prominence, if sea level rose 56 m, North and South America would be separate continents and McKinley would be 6138 m above sea level. At a slightly lower level, the continents would still be connected, and the high point of the combined landmass would be Aconcagua, the encirclement parent. Note that, for the purposes of this article, man made structures such as the Panama Canal are not taken into account. If they were, the key col would be along the 26 m Gaillard Cut and McKinley would have a prominence of 6,168 m.

Some of the explanation from earlier in the article provides some insight here:

the encirclement parent often does not satisfy the intuitive requirement that the parent peak should be close to the child peak

Source: Topographic prominence - Wikipedia, the free encyclopedia

Chris Donohue, GISP

Re: How do I measure prominence?

AndrewKirmse — Tue, 09 May 2017 18:10:38 GMT

I realize this is an old question, but here's a complete computation of topographic prominence I recently completed:

http://andrewkirmse.com/prominence