"Sunlight Spire" LiDAR Elevation

[Tufftommy-BV]

These two LiDAR threads have been fascinating. As a person who is chipping away at the bicentennial peaks the first thing I thought of was now we can (possibly) find out which of the peaks 198-202 are the highest! I think all five were extrapolated peaks and not surveyed…. Also, since PT 13545 will - at some point - become a tri peak then which which peak falls off, Sundog or Jenkins? Or, possibly, they are both the same elevation within error. Anyway, that would all need to be figured out by someone more tech savvy than I am which is 99% of the population over the age of six.

[aholle88]

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.

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.

If we start counting man made structures, the new summit house on Pikes would bump that up a solid 60+ feet

[greenonion]

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

Thanks!

[Chicago Transplant]

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.

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.

If we start counting man made structures, the new summit house on Pikes would bump that up a solid 60+ feet

On a sort of related topic, what about treed summits? Some of the soft ranked in county or wilderness lists for example are below treeline. Curious if the trees throw the elevation calcs off? Not sure how the LiDAR is affected by foliage.

[Eli Watson]

So am I as cool as the other Eli and TakeMeToYourSummit or not?

[bdloftin77]

On a sort of related topic, what about treed summits? Some of the soft ranked in county or wilderness lists for example are below treeline. Curious if the trees throw the elevation calcs off? Not sure how the LiDAR is affected by foliage.

Fortunately, in the filters there is a Ground class (usually class 2). If we turn that one on, then it filters out many unwanted points, including foliage and buildings. Sometimes it filters out a bit too many points for summits/saddles above treeline, so turning on Unclassified (class 1) can be helpful in those cases. For Sunlight Spire, class 2 filtered out the entire spire! Turning on class 1 enabled me to see the spire/summit block.

Below are some examples of some filtering results for a different summit. It's interesting to see how the LiDAR picks up the trees and the buildings.

Satellite Imagery

Satellite.jpg (222.74 KiB) Viewed 2537 times

Class 1 and 2 (Unassigned and Ground)

Class1and2.jpg (373.6 KiB) Viewed 2537 times

Class 2 (Ground Only)

Class2.jpg (326.19 KiB) Viewed 2537 times

[d_baker]

So am I as cool as the other Eli and TakeMeToYourSummit or not?

What does that even mean? As it relates to this thread.

[peter303]

On a sort of related topic, what about treed summits? Some of the soft ranked in county or wilderness lists for example are below treeline. Curious if the trees throw the elevation calcs off? Not sure how the LiDAR is affected by foliage.

You end up with a blur of measurements ranging from the treetop leaves to the ground reflection. You can select the longest ones to be the ground.

This is pretty important in jungle archeology like the Mayas or Cambodia. (Or the US where forests have reclaimed abandoned farmsteads and villages.) Growth may completely hide buildings in aerial photographs. But enough lidar pings might penetrate to obtain topography.

[DArcyS]

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.

LOJ.PNG (75.94 KiB) Viewed 2359 times

I was wondering where West Eolus would come out, and I see it's at 299', just missing out.

Hmm, now I'm wondering about BoggyB heading up to the saddle and digging out a two-foot pit and requesting John to double check his work.

[constipated_pete]

On a sort of related topic, what about treed summits? Some of the soft ranked in county or wilderness lists for example are below treeline. Curious if the trees throw the elevation calcs off? Not sure how the LiDAR is affected by foliage.

You end up with a blur of measurements ranging from the treetop leaves to the ground reflection. You can select the longest ones to be the ground.

This is pretty important in jungle archeology like the Mayas or Cambodia. (Or the US where forests have reclaimed abandoned farmsteads and villages.) Growth may completely hide buildings in aerial photographs. But enough lidar pings might penetrate to obtain topography.

This other Peter has got it, lidar excels at foliage penetration. Some percent of incoming photons (20% in N. American forests, 5% in jungle) make it through canopy to the ground and a similar make it back up from the ground through the foliage. If you have a powerful laser and a sensitive detector you can clearly see the photons that are reflected by the ground underneath canopy. Here's an outstanding article about archeologists using it to discover lost cities in Central America:
https://www.newyorker.com/science/eleme ... lost-world

[Eli Watson]

So am I as cool as the other Eli and TakeMeToYourSummit or not?

What does that even mean? As it relates to this thread.

I've summited 73/74 of the "List of 74" Colorado 14ers as listed on this site, including the Unranked + Unnamed summits. The only one I'm missing is "Sunlight Spire".

[Salient]

So am I as cool as the other Eli and TakeMeToYourSummit or not?

What does that even mean? As it relates to this thread.

I've summited 73/74 of the "List of 74" Colorado 14ers as listed on this site, including the Unranked + Unnamed summits. The only one I'm missing is "Sunlight Spire".

Well good think Sunlight Spire is under 14000’ now