Largest 'flat' summit?

[Wentzl]

I have not seen Half Peak come into the discussion yet. A contender?

https://www.summitpost.org/half-peak/150626

[jkirk]

This is the custom list Tim had for flattest CO summits:
https://listsofjohn.com/clist?lid=453

These generally are in a class of their own compared to what's been mentioned (aside from 11998).

[Jon Frohlich]

This is the custom list Tim had for flattest CO summits:
https://listsofjohn.com/clist?lid=453

These generally are in a class of their own compared to what's been mentioned (aside from 11998).

Looks like the Flat Tops were just left on that list in general. Maybe there wasn't data available?

[Scott P]

This is the custom list Tim had for flattest CO summits:
https://listsofjohn.com/clist?lid=453

These generally are in a class of their own compared to what's been mentioned (aside from 11998).

Looks like the Flat Tops were just left on that list in general. Maybe there wasn't data available?

I was thinking that too, but ironically perhaps most of the ranked summits in the Flat Tops aren't flat. They are steeper bumps poking up from the flat plateau. The only ones I can think of which are relatively flat are Flat Top, Derby, and 11,998.

[bdloftin77]

This is the custom list Tim had for flattest CO summits:
https://listsofjohn.com/clist?lid=453

These generally are in a class of their own compared to what's been mentioned (aside from 11998).

Thanks, John!

[jkirk]

Looks like the Flat Tops were just left on that list in general. Maybe there wasn't data available?

The issue is method of measurement, as it's least average drop in a 100m radius from the summit, so if there is a nearby dropoff in any direction despite the general area being flat, the flatness measure goes down. Seems like the DEM available at the time wasn't so good for 11998.

[bdloftin77]

Looks like the Flat Tops were just left on that list in general. Maybe there wasn't data available?

The issue is method of measurement, as it's least average drop in a 100m radius from the summit, so if there is a nearby dropoff in any direction despite the general area being flat, the flatness measure goes down. Seems like the DEM available at the time wasn't so good for 11998.

I just asked Joe if he could perform the contour area analysis at a drop of 200', 100', and 50' for all the Colorado ranked peaks. He said he might have that done in a couple months, pending any extra peaks that need to be analyzed to finalize a list of 200. The 300' list is good at capturing steep peaks with very long drops. But the lower drop metrics would capture a lot of high YDS, sharper summits that the 300' list didn't quite catch (eg lower sharp summits that drop a couple hundred feet to more level ground, with the saddle a bit further away. Examples would be ranked Big Rock Candy Mountain and Noddle Heads North, which are mid class 5 but didn't even make the top 200 on the area at 300' drop list).

Thread topic...
The peaks at the lower end of the 50' area list might indicate a decent level of flatness, whereas the lower end of the 300' list could still have a decent amount of elevation variation before you drop 300' despite the 300' drop area being very large (eg Mt Sherman is rather ridge-like near the summit and therefore not very flat in most directions, but it still has a huge footprint when you drop down to 300' below the summit). An even better measure for flatness would be the largest area at a 25' or even 10' drop, but right now we're mainly focused on finding the cooler peaks (steeper) vs the flatter ones.

[Jon Frohlich]

Looks like the Flat Tops were just left on that list in general. Maybe there wasn't data available?

The issue is method of measurement, as it's least average drop in a 100m radius from the summit, so if there is a nearby dropoff in any direction despite the general area being flat, the flatness measure goes down. Seems like the DEM available at the time wasn't so good for 11998.

Ok, that might make sense since 11,998 supposed summit is near the north end of the plateau and there might be a drop to the north within 100m even though you could walk hundreds of meters south on 'flat' ground.

[Eli Boardman]

I always thought the way to do a steepness metric would be to find the maximum distance between the summit and the first drop below X ft. in any direction. In other words, check each azimuth outward from the summit with a pre-defined height threshold (e.g., 300 ft.) and record the minimum distance along that azimuth to achieve the specified drop in elevation. Do this for all azimuths (maybe every 1 deg.) and the "steepness" is the maximum distance required to drop at least X ft. in any direction.

This would have the effect of discounting peaks that sit on sharp ridges or near a cliff edge on a large plateau, since there is at least one direction with a shallow slope (e.g., along the ridgeline). In my mind, a "steep" peak is one that drops rapidly in all directions.

Maybe if I weren't so lazy I would code it up myself...hah.

[bdloftin77]

I always thought the way to do a steepness metric would be to find the maximum distance between the summit and the first drop below X ft. in any direction. In other words, check each azimuth outward from the summit with a pre-defined height threshold (e.g., 300 ft.) and record the minimum distance along that azimuth to achieve the specified drop in elevation. Do this for all azimuths (maybe every 1 deg.) and the "steepness" is the maximum distance required to drop at least X ft. in any direction.

This would have the effect of discounting peaks that sit on sharp ridges or near a cliff edge on a large plateau, since there is at least one direction with a shallow slope (e.g., along the ridgeline). In my mind, a "steep" peak is one that drops rapidly in all directions.

Maybe if I weren't so lazy I would code it up myself...hah.

Nice! Yeah, John had a similar idea for the steepest peaks. Take a predefined drop, like 300', and find the minimum angle (equating with the max distance) from a 360 degree search to achieve that drop. Joe analyzed all the ranked peaks with that metric, a radial area metric, and a contour area metric. John thought that the area at a certain drop actually lead to a slightly higher YDS than the angle (or longest distance) method. See the thread below, though I think John actually used the contour area vs the radial area on LoJ.

https://www.14ers.com/forum/viewtopic.php?t=63543

[Eli Boardman]

Yeah, John had a similar idea for the steepest peaks. Take a predefined drop, like 300', and find the minimum angle (equating with the max distance) from a 360 degree search to achieve that drop. Joe analyzed all the ranked peaks with that metric, a radial area metric, and a contour area metric. John thought that the area at a certain drop actually lead to a slightly higher YDS than the angle (or longest distance) method. See the thread below, though I think John actually used the contour area vs the radial area on LoJ.

https://www.14ers.com/forum/viewtopic.php?t=63543

Cool, I guess I missed that thread. Whom do I need to bribe to get this extended to all the western states, not just CO? Some of the new towers found by lidar in Wyoming would be interesting to compare.

[bdloftin77]

Yeah, John had a similar idea for the steepest peaks. Take a predefined drop, like 300', and find the minimum angle (equating with the max distance) from a 360 degree search to achieve that drop. Joe analyzed all the ranked peaks with that metric, a radial area metric, and a contour area metric. John thought that the area at a certain drop actually lead to a slightly higher YDS than the angle (or longest distance) method. See the thread below, though I think John actually used the contour area vs the radial area on LoJ.

https://www.14ers.com/forum/viewtopic.php?t=63543

Cool, I guess I missed that thread. Whom do I need to bribe to get this extended to all the western states, not just CO? Some of the new towers found by lidar in Wyoming would be interesting to compare.

Joe Grim is your man! And if the bribe is good enough, he'd probably go for it! Otherwise he might be able to tutor you how to use his analysis program if he doesn't have the time or data storage to go for it. He downloaded all the lidar data for Colorado which takes up massive amounts of space. Lending a decent-sized hard drive(s) for other states might be a good bribe if he's low on space.