Re: [prominence] What is Prominence, exactly?
- I suppose there's a fifth (and final?) way which is motivated by what I've
been seeing behind Edward's shoulder as he performs WinProm calculations
of prominence (on my home PC, of all places) :
Just admit ignorance and report the prominence by a range of possible values,
in this case 960-1040 ft. Indeed, WinProm allows one to order the
prominences of peaks in a large list according to several of the 5 possibilities
elaborated by the Ropers and myself: the "dictum" changes depending on
I'm certain EE could explain this better than myself.
Karen & John Roper wrote:
> >Had a lot of fun this weekend figuring the prominence of all the
> >summits (300' drop) and possible summits in the nearby Catalina
> >Mountains (work attached).
> At least in this Prominence group venue, my suggestion is that we list Prominence numbers in the "clean, clear, unequivocal way," as the so-called "finest" lists have done, where the Prominence value cannot be disputed as being less than stated. I'm afraid this may wipe out a few summits in lists that are calculated by the "split the difference" method below (which may be more statistically accurate).
> What does the group think? How many Colorado 11,12, 13, and 14,000ers by a 300-foot shoulder drop get bumped off their list when the "clean" prominence rule is applied? How would this affect AZ? So far in Washington we haven't worried about this yet, since we are still trying to get around to the 400-foot P peaks, and our list-makers generally use the "clean" method.
> John Roper
> Ways to Calculate Prominence
> John Roper
> As an exercise, let's try to figure the Prominence of a theoretical peak that shows as the 7000+ foot contour, where the pass/saddle that connects it to the next higher peak shows as the 6000+ foot contour, by the various ways:
> 1) "Clean Prominence Way" = 960 feet.
> Dictum: Let no one dispute that this peak qualifies for this Prominence level.
> Therefore, make the peak as low as the map allows, and make the saddle/pass to the next higher peak as high as the map allows, or on 40-foot contour maps, add 40 feet to the contour shown for the saddle (taking the contour that encircles the peak, but no higher summit).
> For example, a 7000+ foot contour peak remains 7000 feet and the 6000+ pass would be figured at 6000' + 40' = 6040', for a Prominence of 960 feet.
> 2) "Best Possible Prominence Way" = 1039 feet.
> Dictum: Make the peak's prominence look as good as possible.
> Make the peak as high as possible, and make the pass/saddle as low as the map allows.
> For example, a 7000+ foot contour peak could be as high as 7039 feet on a 40-foot contour map, and the 6000+-foot pass could be as low as 6000 feet, so the best Prominence possible is 1039 feet.
> 3) "Call a Spade a Spade Way" = 1000 feet.
> Dictum: Whatever the map says the elevation of the peak and the pass is, is.
> For example: A 7000+ foot contour peak = 7000', and a 6000+ foot contour pass = 6000', so the Prominence is 1000 feet.
> 4) "Split the Difference Way" = 1000 feet.
> Dictum: Add 20 feet (1/2 of a 40 foot contour) to the peak, and add 20 feet to the pass before the subtraction.
> For example: A 7000+ foot contour peak = 7020' +/-20, and a 6000-foot contour pass = 6020' +/-20, for a Prominence of 1000 feet.
> [Non-text portions of this message have been removed]
- Adam Helman wrote:
>I have just a brief addendum to this. Winprom can sort peak lists in 6
> I suppose there's a fifth (and final?) way which is motivated by what I've
> been seeing behind Edward's shoulder as he performs WinProm calculations
> of prominence (on my home PC, of all places) :
> Just admit ignorance and report the prominence by a range of possible values,
> in this case 960-1040 ft. Indeed, WinProm allows one to order the
> prominences of peaks in a large list according to several of the 5 possibilities
> elaborated by the Ropers and myself: the "dictum" changes depending on
> your philosophy.
ways: by elevation or by prominence, and by the highest, midpoint, or
lowest possible values of each of these quantities. Although it can
sort the list in 6 ways, it can filter the list only by highest possible
prominence (actually, you can prune further by elevation, but that's an
unrelated matter). If you ask for all peaks with at least 1000'
prominence, you will get a list of all peaks that have any possibility
of at least 1000' prominence (hence the unconditional use of the highest
possible prominence as a criterion for inclusion in the list).
Winprom's philosophy is to list all possibilities, to leave no stone
unturned. You cannot choose another dictum.
Edward "7.389056099" Earl