Been using Google earth on dialup -- very useful, in some respects, but
slow. It's way too fuzzy to help much in lat/long measurements in my 'hood,
but it does give elevation where the pointer is, and that seems quite
accurate.

In fact, using the Google elevation data gave me the info I needed to
complete a gravity water system from a spring about 0.3 miles away from our
house. After building a water holding pond, we checked true levels using
some existing piping and a long garden hose. It was right on. (To my great
relief, and my neighbor's astonishment. And mine.)

Take care, Will