New height determined for Denali by USGS

Denali? You mean Mount McKinley?

Now all those people that have climbed it have to go back and climb that extra ten feet.

Dan Patterson, post: 335605, member: 1179 wrote: Denali? You mean Mount McKinley?

Apparently Denali is ten feet higher than McKinley.

The new height is ten feet LOWER...

Well I misread that one. Dang it.

Now they have to dig a 10' hole at the base and climb down into it I guess.

GeeOddMike, post: 335609, member: 677 wrote: The new height is ten feet LOWER...

Apparently the weight of the naming controversy has taken its toll on the mountain.

I feel sorry for the surveyor that used any monuments to bench for an elevation. If FEMA sees this, everything is in a flood zone.

GeeOddMike, post: 335604, member: 677 wrote: http://www.usgs.gov/blogs/features/usgs_top_story/new-elevation-for-nations-highest-peak/?from=title

The ten-foot difference is attributed to improved measurements not geophysical changes.

Some nice photos in this article as well as here: http://www.usgs.gov/newsroom/article.asp?ID=4312#.VfAVP8T3arV

BTW, the radar survey height which prompted this determination was found to be inaccurate.

It has to be asked, what will the "new" adjustments do to this elevation?

The links below are (respectively) an image of the changes to ellipsoid heights, a presentation on the state of the vertical network in Alaska, a file on height issues in Alaska and an image of the USGG geoid-ellipsoid separations in Alaska.

http://www.ngs.noaa.gov/heightmod/AK20107ProbsWVerticalRefFrameIn0AKOppegard.ppt

http://www.ngs.noaa.gov/heightmod/201404KinsmanNGShtModernizationForOnline.pdf

GeeOddMike, post: 335619, member: 677 wrote: The links below are (respectively) an image of the changes to ellipsoid heights, a presentation on the state of the vertical network in Alaska, a file on height issues in Alaska and an image of the USGG geoid-ellipsoid separations in Alaska.

http://www.ngs.noaa.gov/heightmod/AK20107ProbsWVerticalRefFrameIn0AKOppegard.ppt

http://www.ngs.noaa.gov/heightmod/201404KinsmanNGShtModernizationForOnline.pdf

It looks like Alaska will get about a 1.5' increase in ellipsoid heights, will the geoid models get a 1.5' decrease or will that be independent of any ellipsoid changes?

My reading of the contours shows the differences in ellipsoid heights to range from 0 meters in SE, +0.5m in the middle, and +1.0 m in the Aleutians.

The changes to ellipsoid heights should be dominated by translation changes (origin differences). Doing a quick calculation using the itrf96 to nad83 translations (Tx = 0.991, Ty = -1.9072, Tz =-0.5129), I see the about 0.4 m at a point in Denali Borough.

The geometric geoid should be independent and not "contaminated" by the "inseparability" problems posed by data like the GPS on BM data.

GeeOddMike, post: 335680, member: 677 wrote: My reading of the contours shows the differences in ellipsoid heights to range from 0 meters in SE, +0.5m in the middle, and +1.0 m in the Aleutians.

The changes to ellipsoid heights should be dominated by translation changes (origin differences). Doing a quick calculation using the itrf96 to nad83 translations (Tx = 0.991, Ty = -1.9072, Tz =-0.5129), I see the about 0.4 m at a point in Denali Borough.

The geometric geoid should be independent and not "contaminated" by the "inseparability" problems posed by data like the GPS on BM data.

At the end of the day, there will be new ellipsoid heights and a totally new Geoid Model, based completely on gravity measurments, at least I think that's the plan, and although the land at Denali will have a rise of .4m it may still have the same elevation. Or it may grow again;-)

Dan Patterson, post: 335605, member: 1179 wrote: Denali? You mean Mount McKinley?

You only call it that if you are from Outside.

I was joking and I call it that in honor of President William McKinley.