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#75836 - 05/03/10 06:55 AM 14508'
Doug Sr Offline


Member

Registered: 12/16/02
Posts: 2034
Loc: Whitney
Hi Most current elevation of Mount Whitney. Some are still using the bench of 1405 that is about 4' lower . And one group is still holding the 14,497.61 .Thanks Doug

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#75846 - 05/03/10 09:43 AM Re: 14508' [Re: Doug Sr]
Sierra Cement Offline
Member

Registered: 04/22/05
Posts: 172
Loc: Oceanside, CA
Originally Posted By: Doug Sr
Hi Most current elevation of Mount Whitney. Some are still using the bench of 1405 that is about 4' lower . And one group is still holding the 14,497.61 .Thanks Doug

Doug, thank you for the update on the altitude of Whitney. I'm wondering where your source was for this. I'm not disagreeing with you or asking that to make an argument. I'm just asking where one would go to find this kind of information.

Thanks!!

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#75851 - 05/03/10 11:46 AM Re: 14508' [Re: Sierra Cement]
JimQPublic Offline
Member

Registered: 04/18/08
Posts: 196
Loc: California
I'm not Doug, but I do measure things for a living. The 14508' elevation seems to be supported. Note that the difference between the old 14,494' and 14,508' is mostly because of improved surveying technology, an updated national elevation datum, and the difference from the monument to the highest rock, not 14' of uplift.

I seem to recall a project by Fresno State surveying students to get better numbers on Whitney, North Pal, and White a few years back. Not finding that article, here's what I get reading National Geodetic Survey datasheets:

It looks like 14502.7' of point "14501" with Point ID GT0237 is the most accurate surveyed value- but not the highest benchmark. The 14508' value for GT1810 says "The orthometric height was scaled from a topographic map." In other words this survey mark is not a vertical benchmark.

Point "Whitney" with PID GT1811 has a value of 14505'. (Notice no value after the decimal point indicating a lesser quality elevation). But presuming this point is in fact 2' higher than point "14501", let's call it the highest benchmark. In the notes for "Whitney" it says:
Quote:
GT1811'A U.S. GEOLOGICAL SURVEY ALUMINUM PLAQUE IS SET FLUSH WITH
GT1811'THE HIGHEST POINT OF A LARGE BOULDER. IT IS 0.91 METERS HIGHER
GT1811'THAN THE STATION MARK.

If we add 0.91 meters, or 3' to the 14,505' benchmark elevation we get 14,508 for the plaque.

These values are North American Vertical Datum of 1988. This datum is tied to mean sea level at St. Lawrence River vs the older National Geodetic Vertical Datum of 1929 which was tied to tidal benchmarks on both coasts. In lowland California the '88 value for a point is typically about 3' higher than the '29 value for the same point. Mountains change the differential.

Point 14501 is 14496.5' in NGVD '29, and 14502.7' in NAVD '88 for a difference of 6.2'.

Here are the NGS datasheets:

PID GT1811
PID GT0237


Edited by JimQPublic (05/03/10 01:01 PM)

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#75856 - 05/03/10 01:52 PM Re: 14508' [Re: JimQPublic]
Jeff M Offline
Member

Registered: 03/23/05
Posts: 589
Loc: California
So many numbers...

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#75857 - 05/03/10 02:46 PM Re: 14508' [Re: Jeff M]
luciano137 Offline
Member

Registered: 04/09/10
Posts: 129
Loc: OC, CA

As long as it doesn't grow by a few hundred feet, who cares, right smile ?

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#75863 - 05/03/10 05:10 PM Re: 14508' [Re: luciano137]
Doug Sr Offline


Member

Registered: 12/16/02
Posts: 2034
Loc: Whitney
Hi The serious problem is White Mountain also was adjusted and several in Colorado are now higher, since the sea level was lowered to make the dikes around the Gulf higher and save the cost of building the berms taller. Will the snow stay longer with the new elevation ? It would follow the 3-5 delta factor so logic says yes. With all the snow reports of a record year will the rates go down and will the runoff pick up above the current 65 % . 81 degrees North of Big Pine today if this is projected it will be 107 by June 23 and the older folks will do just fine .Thanks Doug

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#75865 - 05/03/10 05:56 PM Re: 14508' [Re: Doug Sr]
MooseTracks Offline
Member

Registered: 08/15/06
Posts: 2389
Loc: B-town Eastside, CA
Sheesh, Doug, that even took me a minute... and I thought I had a pretty good handle on Portal-ese... crazy
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#75940 - 05/06/10 11:39 AM Re: 14508' [Re: MooseTracks]
Doug Sr Offline


Member

Registered: 12/16/02
Posts: 2034
Loc: Whitney
Hi Thanks Jim for the link to noaa.gov/ ngs site Many may not understand the jargon but at least they have the site. This is the site that you can search out a control point for x,y,z data also you can read how to get there and the most current info.


If you have time read the history of the USGS, NGS USGLO and Noaa. if you are interested in GPS this site shows the ongoing datum search, how do you study a surface that is changing and not sure what it looked like when you started. Some very complex models that strive for a "best fit".


You can also download software that allows you to do your own reductions of data. The program that I tell people to download is by Snay , his program allows the input of a time a place and where it is going in California or where it was.


The Frenso study was done as a student project , the El. of Whitney was 14501 again all of this is based on the known Elevation of other points. GPS can measure very small movements and display elevations but this is all software magic and based on known Benchmarks . The movement is real it is what you tie the difference to.


Another point of interest is research how a tidal station is set and the years to establish a new station.

Ok the last clue is the earth as a mass stable at the center ,on the surface , near large bodies of water or near large land masses? So the shift for a reference point may turn out to be not Earth centered it may be from the orbit of the space vehicles. But like the 300 ' change in mapping for the NAD 27/NAD83 some folks will not be happy. Oh the elevation of Whitney about 15,000'. Thanks Doug

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#75947 - 05/06/10 03:21 PM Re: 14508' [Re: Doug Sr]
jimbozoom Offline
Member

Registered: 01/08/10
Posts: 61
Loc: Laguna Niguel, CA
Now that it's a few feet higher, will the success rate go a few points lower?

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#75950 - 05/06/10 04:29 PM Re: 14508' [Re: jimbozoom]
luciano137 Offline
Member

Registered: 04/09/10
Posts: 129
Loc: OC, CA
Originally Posted By: jimbozoom
Now that it's a few feet higher, will the success rate go a few points lower?


I think you will need oxygen laugh

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#75952 - 05/06/10 05:12 PM Re: 14508' [Re: luciano137]
MooseTracks Offline
Member

Registered: 08/15/06
Posts: 2389
Loc: B-town Eastside, CA
Originally Posted By: luciano137
Originally Posted By: jimbozoom
Now that it's a few feet higher, will the success rate go a few points lower?


I think you will need oxygen laugh


Yeah, I think my threshold is 6100vf for the day. 6105ft might just kill me. Better hang up the boots now... laugh
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#75957 - 05/06/10 05:53 PM Re: 14508' [Re: MooseTracks]
bulldog34 Offline
Member

Registered: 07/26/09
Posts: 554
Loc: Atlanta
Originally Posted By: MooseTracks
Yeah, I think my threshold is 6100vf for the day. 6105ft might just kill me. Better hang up the boots now... laugh


Laura, correct me if I'm wrong, but didn't we see 10,000 vf a few weekends ago?

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#75960 - 05/06/10 06:33 PM Re: 14508' [Re: bulldog34]
MooseTracks Offline
Member

Registered: 08/15/06
Posts: 2389
Loc: B-town Eastside, CA
Musta been a typo. wink
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#75961 - 05/06/10 06:35 PM Re: 14508' [Re: MooseTracks]
bulldog34 Offline
Member

Registered: 07/26/09
Posts: 554
Loc: Atlanta
Originally Posted By: MooseTracks
Musta been a typo. wink


Hmmmm . . . I didn't know SPOT could type. Another stupid dog trick I suppose.

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#75966 - 05/07/10 03:58 AM Re: 14508' [Re: Doug Sr]
Wayne Offline
Member

Registered: 01/12/03
Posts: 715
Loc: Charlotte, NC
Wow, Doug, 14,508 feet! Thanks for posting.

Thanks, JimQPublic, for your incisive write-up. I too measure for a living, but I do my measurements through statistical analysis. I also measure with a surveyor's transit, compasses, altimeters and GPS devices for fun, as a hobby. And thanks for the links to the NGS data sheets. I had studied them years ago, but I appreciate the refresher. I missed the 3-foot addition to Mt. Whitney's height (that is, the obliterated "aluminum plaque" that is 3-feet higher than Mt. Whitney's GT1811 station mark).

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#76014 - 05/08/10 06:36 PM Re: 14508' [Re: Doug Sr]
burtw Offline
Member

Registered: 09/05/06
Posts: 371
Loc: Los Angeles
I would have thought they would have had to blast a few feet off the summit to make a level footing for the lift cable tower on top. But maybe they're measuring from the roof of the Starbucks building.

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#76149 - 05/12/10 11:22 AM Re: 14508' [Re: burtw]
JimQPublic Offline
Member

Registered: 04/18/08
Posts: 196
Loc: California
I just realized that there is a separate data sheet for the plaque mentioned above. It gives elevation as 14508'.
NGS Data Sheet for plaque- PID GT1809 Although it says "The orthometric height was scaled from a topographic map", in fact it was established by adding 3' to "Whitney" PID GT1811. If you scale anything from either published topo maps or the NGS DEM you won't get above 14,500'. I suspect PID GT 1810 may also be based on a vertical difference from GT1811.


Edited by JimQPublic (05/12/10 11:28 AM)

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#76170 - 05/12/10 07:36 PM Re: 14508' [Re: JimQPublic]
Wayne Offline
Member

Registered: 01/12/03
Posts: 715
Loc: Charlotte, NC
JimQPublic, you mentioned a recollection about a Fresno State survey. Well, I found the article called "A Tale of Four Summits" which appeared in the April 1998 Professional Surveyor Magazine. It is now in the Magazine's archives, and you can take a look at it here.

Re-reading the article, which we discussed in a fair amount of detail on this board back in 2003, I now see that the head of the project, Robert Nielsen, did NOT remeasure Mount Whitney, since his crew never got to the summit back in June 1996 when the survey was done. Robert quoted a figure of 14,500 feet for Mount Whitney, but he was merely rounding off the figure. He did get exacting measurements for Williamson, the North Pal and White Mountain Peak.

The whole purpose of the survey was to determine the precision and possibility of improving vertical viewing angles for low-level GPS satellites by GPS receivers. His project was successful in that regard. The new measurements for Williamson, North Pal and White Mountain were just a bonus. But the important matter for us here is that Robert Nielsen did not measure Mt. Whitney. The Whitney survey crew had two $50,000 Trimble GPS receivers, but they never got to the top of Mt. Whitney to mount them for the grand experiment.

In case you missed the link above, just click here.

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