Soft peaks

[Timothy Kaye]

I noticed that X-Prime has been adjusted to 297 feet of prominence based on LIDAR. However it does not have a soft peak designation. With LIDAR is soft peak designation obsolete?

[JoeGrim]

With LIDAR is soft peak designation obsolete?

"Soft ranked" just means that the best available data indicates it could be ranked, but is likely not. With topo map data, soft ranked peaks were those whose range of prominences encompassed 300', but it's best estimated prominence is less than 300' (e.g., a peak with seven 40' contours around it and no summit or saddle point elevations could have a prominence between 240 - 320', but the interpolated prominence is 280'.) With LiDAR data, this breadth of possible prominences has been greatly narrowed to only one foot; this is because the absolute elevation accuracy at the 95% confidence level is 1 foot (for most LiDAR data). So, for peaks with LiDAR coverage, the only ones that are soft ranked are those with 299'-299.99' of prominence.

A caveat is that there may be a few peaks with less than 299' LiDAR prominence that might actually be ranked. Things that could cause this include: a very sharp pointy rock at the summit that is missed by the LiDAR scan or a summit HP underneath/amidst trees/bushes. For this reason, it will be valuable for people visiting peaks with nearly 300' prominence to take photos of the summit HPs with known objects in the photo for scale. Independently hand levelling will also be helpful, if a HP candidate is sharp or amidst vegetation. This will remain a work in progress, and LoJ will provide the best available information until/unless more accurate information comes along.

[Timothy Kaye]

Thanks Joe. You answered my question. I enjoy your trip reports as well!

[bdloftin]

Thanks Joe! A minor correction - (and this is if I'm remembering correctly) - with a 95% confidence interval centered at a return and spanning +-19.6 cm (~7.7 in.), as well as possibly missing the very tops of rocks or the very bottom of a saddle, John thought rounding would be best. Anything that rounds to 299' (298.5000 to 299.4999) would be in the new soft-ranked category, whereas anything that rounds to 300' (299.5000 to 300.4999) would be ranked, though in the error range. In both of these situations, John is posting notes with the exact elevation (to 4 decimal places) of both the summit and the saddle for the user's information.

[JoeGrim]

Thanks for the corrections, Ben!