Lists of John Analysis

[DSunwall]

Have you seen this?

http://www.vulgarianramblers.org/listsofjohn.php

[JoeGrim]

A bit nit-picky, but then he has the right to come up with his own list for his own reasons. Personally, I find LOJ to be the most objective and accurate source for peak info.

[John Kirk]

Yeah it has been up for a year or so...
Doesn't really hold water (using DEM pretending it yields precise elevations, 12ers should also be listed as 13ers, peaks should be listed if they have maximum possible rise of less than 300 but are close (peaks that fail to be even soft-ranked)).

[BrianR]

I wrote this up this long missive earlier this evening and couldn't decide to post it or not, and it's probably beating a dead horse since John talks about some of this stuff on the LOJ glossary page, but what the heck.

Aside from the listing issues John mentions, there are flaws in the technical analysis. First, using a variety of techniques creates inconsistencies between different peaks and it also implies spurious precision that does not exist. I.e., I don't think you can trust consumer-grade GPS or altimeters or DEM data to better than 20 feet on some sort of 100% basis. (He admits this for the DEM data, while somewhat glossing over the fact that his standard deviation of "only" 5 meters really isn't so great.)

Second, raw altimeter deltas are only a lower bound to the actual delta due to the way most altimeters work and the way the atmosphere works. I.e., unless you are climbing in winter, you will be climbing most high peaks in the lower 48 in warmer conditions than the Standard Atmosphere (which has 8 degrees Fahrenheit at 14,500 feet) and that's the basis for most or all digital altimeters. In particular, the quoted 276-foot saddle depth for Muir could in fact need to be corrected to 300 feet on a warm day (and their measurements were made in July). That's an 8.7% boost and I have measured an effect nearly that large on Colorado 13ers before and I see this a lot in Arizona on warm, quick, medium elevation peaks where there isn't time for significant weather changes. (I have an essay on this technique at:
http://www.eskimo.com/~rachford/mountaineering/essays/altimeter_corr.html)
This technique isn't perfect, but raw altimeter differences during summer are virtually always going to be short.

This is all a long-winded way of agreeing with what John says here and in his glossary page. Although it may not provide a perfect list of peaks, what I like about the LOJ lists is that they are based on a single source and do not depend on any extraneous behind-the-scenes analysis. If one has any doubts, they should be climbing the soft rank peaks to be sure.

[DSunwall]

ok, someone should set the guy straight I suppose.

thanks Brian for that discourse on altimeters, I have friends that battle them continuously, one guy just uses a set percentage to add as he gets higher, seems to work. I am continually baffled by folks who waste money on those things however, for the same dollars you could get a barometric GPS corrected altimeter, almost always pretty close.

[TWorth]

Good altimeter analysis there Brian, very interesting.

A while back I created a excel file which compared USGS elevation of all CO peaks and saddles to the figures yielded by DEMs(specifically, NED at 1/3 second). Don't have a copy of it at the moment, but bascially, the results were all over the place, with the DEM elevations often +-50 ft for both saddles and summits. Seemed to drive home the point that DEM data is unreliable for exact summit/saddle elevations, though I may rerun the analysis with the 1/9 second dataset to see if there is any improvement.

[RyanSchilling]

The only point from VR that I agree with is that John (and those of us who helped with CO) used just one slice of the USGS quads: whichever versions were available on TOPO!. I don't know what could have been done about this, however.

[John Kirk]

The only point from VR that I agree with is that John (and those of us who helped with CO) used just one slice of the USGS quads: whichever versions were available on TOPO!. I don't know what could have been done about this, however.

I checked topoquest, acme, and mytopo versions available online as well. I have changed Versteeg to 13470 as mentioned. Nevertheless, I would argue that there are probably hundreds of cases like this, including CO, where older quads have spot elevations where the newer versions may not. Older maps are often inconsistent with newer ones when looking at spot elevations, so one either gets lucky choosing an elevation that happens to coincide with current maps or one chooses to ignore it - Cafeteria Catholics come to mind....

[RyanSchilling]

I agree fully about past versions of quads. My feeling is that there was a reason those were left out (a possible exception being the foot-measures of mtns that don't have corresponding spot elevations on the metric quads of, say, CA).

How fast does TOPO! publish new versions of quads? My main concern was that TOPO! wasn't updated quickly enough.

I checked topoquest, acme, and mytopo versions available online as well.

For all peaks? You did far more due diligence than I did (might wanna go back and check my work!)

[John Kirk]

For all peaks? You did far more due diligence than I did (might wanna go back and check my work!)

Only for CA 13ers (and some wacky stuff in Park County WY).

TOPO! seems to be a real hit and miss when it comes to the quad updates - seems like they are updated in areas where peopleusethe maps the most (demand-driven)...

[Jeremy Hakes]

Geezus. Just climb the damn things!

Personally, in my experience, altimeters are definitely NOT the way to go for measuring. A few books I have list the "altimeter reading" or the "gps elevation", with a significantly older GPS that is not very accurate, and those elevations are WAY off from the quad (and LOJ).