On 2011-03-31, Uwe Klein <uwe_klein_habertw...@t-online.de> wrote:
> Chris Albertson wrote:
>> Another possibility to check is that both are not using the same
>> system.  What spheroid dose Google use?  Is it WGS84?   The GPS would
>> need to be set to match whatever Google uses.  Errors on the order of
>> up to 100M are posable.  Not everyone uses the same system.
>
> I would not be too surprised if google introduces distortions and errors
> as demanded by some 3letter org.

Using the Canadian National Resources Council Geobase database of survey
monuments in Canada (Vancouver seems to be fy far the most densely
populated area in the whole country with these monuments-- about 300 of
them, while Toronto has about 8.) the one monument at UBC that I have
easy access to (the Flagpole) is within less than 1m of the true
location. That of course does not mean that the locations elsewhere are
equally correct. 

Both the Sure and the Geobase claim to use WGS84 as the ellipsoid.

>
> What about comparing to a known to be good GPS that allows to select the 
> coord system?
>
> uwe

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