Latitude and longitute distances question.?

[Me N]

Hello. I have been geocaching the last few days and I have a question about figuring distances when I am using my GPS to find the caches. Is there a calculator, or a rule of thumb for calculating distances based on the degrees, minutes, seconds into feet?for instance. I am at N 42° 18.362 W 122° 51.646What would be the distance if I moved to N 42° 18.362 W 122° 51.645 (basically one thousandth of a minute)?

[korani60]

You can find helpful text on this address:http://en.wikipedia.org/wiki/Longitude