>
> I would not trust Google-Earth elevation data.To add an example like
> Bimini, Bahamas: Check Malpelo Island, HK0TU, 400 km away from the colombian
> Pacific coast (4.0 N, 81.6 W) According to Google earth the island is
> submerged under the water surface a least 340 ft. In reality, this island has
> elevations over 1000 ft ASL.
>
I think that's a good example of which ellipsoid is being used. if you
move your cursor across some of the islands (little more than rocks
sticking up, it looks like) at 3-49-57.46 N 81-36-15.28W it seems to be
pretty consistently around -80m
If you traverse across the island (center roughly at 4-0-12N 81-36-27W)
you see the altitude smoothly vary from -80 to the SE of the island,
getting gradually lower to -229m (at least) to the NW of the island
In fact, if you look at all the elevations in the area, it runs around
-240m everywhere, and that -60 to -80 seems to form a hump to the SW of
the island. It looks more like it's misregistered between the elevation
grid and the island. Again, that could be how the original photo image
was georeferenced vs what the elevation data was referenced against in
terms of datum
Given the extreme depths (<-1000m) not too far away, I'm going to guess
that Google Earth is returning bathymetry data.
So, I'd say a combination of spheroid and data set mismatches.
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