How to verify that Google Earth uses WGS84

I have found that Google Earth utilizes the WGS84.  How can
I verify
this to be true using current Google Earth tools?


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GeoGregory3gmail.com wrote:
> I have found that Google Earth utilizes the WGS84.  How
can I
> verify this to be true using current Google Earth
tools?

If not WGS84, then what?  Most other datums are local in
nature
(i.e., not geocentric) and thus are not suitable for global
mapping.
The U.S. Department of Defense did develop a couple of
geocentric datums prior to adopting WGS84, but the use of
those
has been discontinued.  WGS84 is pretty much our only
option.

If your question is whether Google Earth elevations are
referenced
to the ellipsoid (GRS83) or to the geoid (i.e., true mean
sea level),
I'd guess its the geoid.  Ellipsoid elevation is relative
to an
imaginary flattened sphere (an ellipsoid), which is merely a
simplified mathematical model roughly approximating mean sea
level.  Since it makes little sense to place oceans at an
elevation
different than zero, I doubt Google chose ellipsoid
elevation.


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Let me restate my question:  If I know for a fact that
Google Earth
uses the WGS84, how can I verify that using any of the
Google Earth
tools (e.g. by measuring distances between two points or by
noting the
lat/long of a key geolocation -- like the Empire State
Building)?


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Let me restate my question:  If I know for a fact that
Google Earth
uses the WGS84, how can I verify that using any of the
Google Earth
tools (e.g. by measuring distances between two points or by
noting the
lat/long of a key geolocation -- like the Empire State
Building)?


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GeoGregory3gmail.com wrote:
> Let me restate my question:  If I know for a fact that
Google Earth
> uses the WGS84, how can I verify that using any of the
Google Earth
> tools (e.g. by measuring distances between two points
or by noting the
> lat/long of a key geolocation -- like the Empire State
Building)?

I don't think you can.  While map features are placed
according
to their WGS84 position, they are projected onto a sphere,
not
the GRS83 ellipsoid.  So the distances would be distorted
from
true great circle arch measurements.


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GeoGregory3gmail.com wrote:
> Let me restate my question:  If I know for a fact that
Google Earth
> uses the WGS84, how can I verify that using any of the
Google Earth
> tools (e.g. by measuring distances between two points
or by noting the
> lat/long of a key geolocation -- like the Empire State
Building)?

I don't think you can.  While map features are placed
according
to their WGS84 position, they are projected onto a sphere,
not
the GRS83 ellipsoid.  So the distances would be distorted
from
true great circle arch measurements.


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GeoGregory3gmail.com wrote:
> Let me restate my question:  If I know for a fact that
Google Earth
> uses the WGS84, how can I verify that using any of the
Google Earth
> tools (e.g. by measuring distances between two points
or by noting the
> lat/long of a key geolocation -- like the Empire State
Building)?

I don't think you can.  While map features are placed
according
to their WGS84 position, they are projected onto a sphere,
not
the GRS83 ellipsoid.  So the distances would be distorted
from
true great circle arch measurements.


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