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$Paul Hirose: Re: Any reliable computation of terrestrial refraction?$

Re: Any practical Method to obtain WGS84 Altitudes?
From: Paul Hirose
Date: 2024 Mar 25, 22:29 -0700

> *From: *Antoine Couëtte
> *Date: *2024 Mar 24, 17:14 -0700
>
> I performed all my computations
> 
 assuming 
that such WGS84 referenced altitudes are obtained directly from Google Earth 
[Pro], but since the exact shorelines seem to always show at 0 m altitude - 
which should not be the actual case everywhere - I am not sure that Google 
Earth [Pro] actually indicates such WGS84 referenced altitudes.

Apparently Google shows orthometric height, not height above ellipsoid.
You can obtain the latter by subtracting geoid height. The US National
Geospatial Agency has an online calculator. I think it works everywhere
in the world. At the location of the photo the geoid is about 45 meters
above the WGS84 ellipsoid.

https://earth-info.nga.mil/

--
Paul Hirose
sofajpl.com

$Paul Hirose: Re: Any reliable computation of terrestrial refraction?$

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