Re: Google Earth ruler question
At higher elevations, the map scale is slightly off. The "map distance" does not account for the fact that an inch on the map in Leadville is not the same as an inch on the map in San Diego. Ground distance accounts for that. So the ground distance should be closer to your RF reading. I just did a test and the ratio over the Gulf of Mexico was 1.005 map length per ground length. In the Himalayas, it was 0.99 map length per ground length, due to the ~15,000 feet of elevation difference.