Page 2 of 2

Re: Peak lists are changing!

PostPosted: Tue Dec 21, 2021 7:38 pm
by mikeofferman
I think that the saddle for Yale is off by 1k


# Name Map Elevation Map Saddle Map Prominence LiDAR Elevation LiDAR Saddle LiDAR Prominence
40 Yale, Mount 14,196' 12,300' 1,896' 14,200' 13,326' 874'

Re: Peak lists are changing!

PostPosted: Tue Feb 01, 2022 5:11 pm
by bdloftin
jmbrooks,

Here's a useful link with all the info you wanted (or didn't want) to know about the USGS 3DEP lidar base specifications.
https://www.usgs.gov/ngp-standards-and- ... e-contents

Regarding nominal pulse spacing and vertical accuracy, see this link: https://www.usgs.gov/ngp-standards-and- ... ion-tables
The USGS is wanting to fill the CONUS and Hawaii with Quality Level 2 lidar data (Alaska will be covered by interferometric synthetic-aperture radar).

Regarding coordinate systems/datums, see here: https://www.usgs.gov/ngp-standards-and- ... nts#datums
For the vertical datum, they were first required to use GEOID12 iterations, but are now going with GEOID18 which differs from the former by less than a couple centimeters.

Re: Peak lists are changing!

PostPosted: Sun May 22, 2022 4:43 pm
by jmbrooks8
I just noticed you are updating the coordinates of LiDAR based peak data with 5 digits. I think that is fantastic. I believe in CO that is ~ +/- 2 ft.
Sure appreciate the extra accuracy & precision.

I've checked some of my old summit gps pts and the new data definitely aligns better.

Re: Peak lists are changing!

PostPosted: Mon May 30, 2022 3:22 am
by JoeGrim
bdloftin wrote:Regarding nominal pulse spacing and vertical accuracy, see this link: https://www.usgs.gov/ngp-standards-and- ... ion-tables


Thanks for the links! I had wondered about the absolute vertical accuracy, and now I know! It makes sense how peaks with 299-300' LiDAR prominence are now the new soft ranked, since the accuracy for level 2 data is about 1 foot.

Re: Peak lists are changing!

PostPosted: Mon Jun 06, 2022 5:44 pm
by CandaceS
Tee-hee, Pennsylvania has a new high point, per Lidar :-D

https://listsofjohn.com/peak/218278

Re: Peak lists are changing!

PostPosted: Tue Jun 07, 2022 10:39 am
by jmbrooks8
wow - I see all the 50 StHP completers back @ 49
this LiDAR stuff is getting ridiculous
seems like all lists suspect until all peaks analysis completed
why isn't the USGS working on updating their maps?

Re: Peak lists are changing!

PostPosted: Thu Jun 09, 2022 5:43 pm
by jmbrooks8
This PA StHP change is definitely a test for the purists & climbing community integrity.
How will this be treated? Will anyone/everyone accept the fact they have not climbed this state's HP?
1 ft ??????

Thanks a lot PA! don't even know where your HP is, ugh!
surely this info was available a lot longer ago, c'mon

Re: Peak lists are changing!

PostPosted: Fri Jun 10, 2022 4:56 am
by jmbrooks8
Regarding PA StHP, even Google Earth shows the correct elevations (3213' vs. 3214') of Mt Davis vs. the new StHP area.
They are 0.9 mi apart.
Since the map doesn't show the correct contours & there is no path, I don't see how anyone would have visited this point before, unless they scanned GE.
New pt is 334 ft from nearest road & fortunately still on public land (Somerset Co).

Re: Peak lists are changing!

PostPosted: Thu Jun 23, 2022 11:17 am
by RyanSchilling
jmbrooks8 wrote:Regarding PA StHP, even Google Earth shows the correct elevations (3213' vs. 3214') of Mt Davis vs. the new StHP area.


Hiding in plain sight!