NASADEM only 8781 meters for Mt. Everest?

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lihaijun
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NASADEM only 8781 meters for Mt. Everest?

by lihaijun » Wed Jun 16, 2021 5:01 am America/New_York

Dear All,

I downloaded the tile of "NASADEM_HGT_n27e086" from Earthdata Search. However, the maximum elevation in this tile is only 8781 meters, which is not equals to the elevation of Mt. Everest (8848 meters). What causes the large difference here? If this is caused by the vertical uncertainty, how could we trust the vertical accuracy in other regions?

Thanks,
Haijun

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LP DAAC - jwilson
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Re: NASADEM only 8781 meters for Mt. Everest?

by LP DAAC - jwilson » Wed Jun 16, 2021 5:20 pm America/New_York

We are forwarding your inquiry to our Subject Matter Expert for further assistance.

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Re: NASADEM only 8781 meters for Mt. Everest?

by LP DAAC - jwilson » Wed Jun 23, 2021 1:20 pm America/New_York

The user is right about what he observed w/ the NASADEM tile.

The NASADEM User Guide doesn't have any information on its vertical accuracy. It's based on SRTM (along with few other DEMs), which does full fill mission performance requirements of 16 m absolute vertical error. I don't know what's causing the large difference. We have reached out to our science experts for any guidance.

lihaijun
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Re: NASADEM only 8781 meters for Mt. Everest?

by lihaijun » Thu Jul 15, 2021 1:34 am America/New_York

Are there any updates about this issue from the experts?

Thanks,
Haijun

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Re: NASADEM only 8781 meters for Mt. Everest?

by LP DAAC - jwilson » Fri Jul 16, 2021 10:57 am America/New_York

Our Subject Matter Expert is still waiting a response from the PI.
We apologize for the delay.

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Re: NASADEM only 8781 meters for Mt. Everest?

by LP DAAC - jwilson » Tue Aug 03, 2021 10:54 am America/New_York

Dear Haijun,
As mentioned in the previous reply it's based on SRTM (along with few other DEMs), which does full fill mission performance requirements of 16 m absolute vertical error. At this time the Private Investigator (PI) has not replied to our request for further guidance. We apologize for the inconvenience.

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