5 replies to this topic

[Andrew]

Hello all,

I was wondering if anybody out there knows the horizontal datum which Google Earth uses.
I had done a bit of looking and so far all evidence points to WGS 84, which I am
willing to accept. However when creating a custom KML file and adding WGS
coordinates they do not seem to agree with that of Google earths. This is frustrating because when I hover the cursor over the location which I am concerned in it shows the same coordinates as what I coded but wont bring them together.

Just wondering if anyone has come across the answer, from what I have read
google is extremely helpful when people come across problems but they seem to
want to keep the answer to this one a secret.

Thanks all

[frax]

just some googling gave some info: see this one for instance.

[Martin Gamache]

Frax, that link didnt really answer Andreew's question....

I do know the main landsat. imagery they are using was originally generated in WGS 84...it is the same dataset available from GLCF.

mg

[frax]

the link I posted, and other things you find when you google for information confirms that the datum is WGS84.

What you might want to do is to turn off the terrain (if you haven't done it already), it could be possible that the DEM related things complicate the precision.

[Hans van der Maarel]

One thing to keep in mind is that there is a slight mismatch between the raster and vector data in GE. The raster data is somewhat shifted, at least in the areas I checked.

[Rick Dey]

The Raster data is not necessarily orthorectified and it is very common to see huge shifts along seams.