One should be cautious - I noticed two distinct errors in Goggle Earth's rendering of our local roads - in about five minutes inspection. One was fairly harmless, but not the other one.
google maps shows almost 3/4 mile of a road that does not actually exist inside one of the forest preserves I hike in regularly.
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Warning - I am not an expert on anything having to do with this forum, but that won't stop me from saying what I think.

Bob