"Sunlight Spire" LiDAR Elevation

[CheapCigarMan]

No matter how you slice it.
It’s still just another feature on a ridge.

[Oman]

To simplify things, let's pretend that we're standing right on the ellipsoid (ellipsoid height = 0).

I had such high hopes.

[HikerGuy]

There's a lot of talk about Sunshine Peak. To clarify, are we applying upcoming changes to the newer NAVD88 elevation, 14,006/7', or the older NGVD29 elevation, 14,001'? The newer elevations never really made it out to the various checklist sites and maps, but I do see them referenced on informational sites like peakbagger, summitpost, etc. Demotion seems like a moot point if it is the former, or is it not that simple?

[CheapCigarMan]

I thought it was that simple.
Survey equipment. Lasers. Prisms. Theodolites.
But after reading this tread. Apparently it’s not.

[painless4u2]

Sunlight Spire. The Cameron Peak of the Needle Mountains. Only more technical.

[bdloftin77]

There's a lot of talk about Sunshine Peak. To clarify, are we applying upcoming changes to the newer NAVD88 elevation, 14,006/7', or the older NGVD29 elevation, 14,001'? The newer elevations never really made it out to the various checklist sites and maps, but I do see them referenced on informational sites like peakbagger, summitpost, etc. Demotion seems like a moot point if it is the former, or is it not that simple?

The screenshot/map near the very beginning of my initial post would drop the NAVD88 elevations by ~40 - 80 cm.

Here's another interesting thread related to this topic from earlier this year that I'd missed: viewtopic.php?f=2&t=59615&hilit=sunshine+survey

Spiderman had previously surveyed Sunshine Peak (see bottom of page 1 from above link; and direct thread link: viewtopic.php?style=10&f=2&t=46406), getting an elevation of 14,001.8 +-0.7 ft. Carl_Healy plugged it into the xGeoid20 model, squeaking out at half a foot over 14,000 ft for 2022. Since his error range was +-0.7 ft, it's still debatable based on that survey if Sunshine will be safe. I'll take a look and see what the LiDAR data says. Spiderman used Geoid12A, which is very similar to Geoid12B (https://geodesy.noaa.gov/GEOID/GEOID12B ... _FAQ.shtml). Geoid18 is the most recent official US geoid, though many companies working with ground control points, imagery, and LiDAR still like to use Geoid12B.

Here's two other resources (slide shows) for the upcoming 2022 model:
https://ctgis.uconn.edu/wp-content/uplo ... CT_GIS.pdf
https://www.ngs.noaa.gov/web/science_ed ... upload.pdf

[onebyone]

So, it's a spire, not a mountain?

[aholle88]

I couldn't care less about the ranked/ unranked crap, but this process is super cool. Thanks for sharing.

Ditto on that. These last couple of threads have been very cool and educational in the nerdy mountaineer/peak bagging sense of things. Also, maybe Jkirk should look into hiring Mr Loftin for assisting with LoJ.

[Will_E]

Any data on whether Sunlight Spire has 300’ prominence? Making it now the highest 13’er?

I took a quick look at the saddle, and found it to be between 4203.3 and 4203.5 m. 4203.35 is a pretty good estimate. This would put the prominence at ~62.63 meters, or ~205.5 ft (4265.98m - 4203.35m). This is actually relatively close to the interpolated prominence at 215 ft, though it definitely doesn't always work out that way.

SunlightSaddle1.png

SunlightSaddle2.png

Nice. This stuff makes my Arkansas public schools educated brain hurt, you’re a rocket scientist as far as I can tell.

[bdloftin77]

I'm interested if this affects some of the "close" 14ers like Sunshine and Grizzly peak.

Sunshine Peak: The highest point is 4269.2 m, or 14006.56 ft. In case that's recording a summit cairn, there are quite a few points nearby reading over 4268.5 m, or over 14,004.27 ft. Looks like Sunshine is safe! This area is in the same project area as Sunlight Spire. Vertical accuracy was required to be below 19.6 cm; actual results were 6-7 cm for non-vegetated areas.

Report: https://prd-tnm.s3.amazonaws.com/index. ... 8/reports/
CO_Southwest_NRCS_2018_D18_Final_Project_Report.pdf


Huron Peak: The highest point is 4269.37 m or 14,007.12 ft. Similar to Sunshine, there are many nearby points at over 4268.5/14,004.27 ft. This project also used Geoid12B, and the LiDAR results had an accuracy of better than 10 cm (see page 21 of report; link below).

Report: https://prd-tnm.s3.amazonaws.com/index. ... 9/reports/
CWCB_Montrose_Lidar_Technical_Report.pdf


Holy Cross: The highest point is 14,005.412, with many nearby above 14,004. Vertical error again is better than 10 cm (page 9), using Geoid18.

Report: https://prd-tnm.s3.amazonaws.com/index. ... 0/reports/
140G0220F0113_CO_SanLuisJuanMiguel_2020_D20_WU_ID213146_Lidar_Mapping_Report.pdf

[bdloftin77]

Grizzly Peak: 13,996.39 ft. Geoid 18, better than 10 cm vertical accuracy, page 21.
https://prd-tnm.s3.amazonaws.com/index. ... 9/reports/
CWCB_Montrose_Lidar_Technical_Report.pdf

Stewart Peak: 4263.707 m or 13,988.54 ft. Geoid18, better than 9.8 cm vertical accuracy, page 1.
https://prd-tnm.s3.amazonaws.com/index. ... 0/reports/
USGS_CO_SanLuisJuanMiguel_3_2020_Summary_Report.pdf

Mt Ouray: 4260.67 m or 13,978.576 ft. Geoid 18, better than 10 cm vertical accuracy, page 21.
https://prd-tnm.s3.amazonaws.com/index. ... 9/reports/
CWCB_Montrose_Lidar_Technical_Report.pdf

[bdloftin77]

Might be getting into the weeds too much, but unless we get field measurements of summit cairns and man-made wind-blocks on our high mountains, being picky about the height to within a few feet might have to factor in man-made summit rock structures. It'd be a subjective call as to whether one measures the highest point of the cairn (or natural pile of rocks?), or to a point near the cairn, or to a point near the curved wind-block rock formation. These are probably only a few feet high usually.

Sometimes a man-made wind-block formation is relatively obvious, such as below on the summit of Hesperus. This looks to be just over 2 ft high, but if the natural summit is hidden in the midst of the wall, it'd be hard to say.

Other times, it's hard to tell if the high point showing up in the LiDAR is an actual summit rock, or the top of a man-made cairn. Again, it's only usually a few feet, which might not be a big issue. Some summits such as Culebra, Rattlesnake Butte (Douglas County near I-25), Phoenix Peak, North Arapaho, or Mauna Kea have massive summit cairns that can be avoided if need be when processing. That would be a subjective call for whoever is analyzing the LiDAR.

In the grand scheme of things, man-made summit rock structures don't matter too much. Only if a peak is very close to being ranked/unranked, near an elevation threshold, or if we are trying to determine tie-breakers between bicentennials, etc would it be more important.

Anyway, cool that things like this show up!

Hesperus Wind-Block Rock Wall

Hesperus Wind-Block Wall.png (101.87 KiB) Viewed 2074 times

Fortunately, sometimes filtering by class can take care of this.

Hesperus Summit - Filtered

Hesperus Filter.png (236.93 KiB) Viewed 2068 times