Mr Mercator

Paul, I guess they are the first, assuming the cacherstats are correct and fairly up to date. Second place has "only" 82,000. It is pretty mind-blowing.Thank you Mr M. Mind-blowing indeed! Congratulations on your own milestone by the way. I remember my 500th like it was only yesterday. It wasn't. I was September 2005. Onwards and upwards! Thanks Paul, looks like you've got a few milestones and been around quite a while, the same year as I found my first cache I think. Someone at a meet once said to me: "you're probably the oldest cacher here". I took it the wrong way until I saw what he meant. Your remote meets look pretty interesting.

Paul, I guess they are the first, assuming the cacherstats are correct and fairly up to date. Second place has "only" 82,000. It is pretty mind-blowing.

On the same weekend I got my 500th (possibly the slowest 500 in Essex, it took over 11 years) I see Alamogul has clocked up his 100,000th find - congratulations to him. Funny old game.

I sometimes use live.geocaching.com on my Nokia 5800 which I really like - excellent for spur of the moment caching, and will even show the position of other cachers on-line if they allow visibility. Not quite as robust as my Garmin (I go out with both), but I still think it is amazing to be able to get all the essential info when you're out and about. Battery life of course isn't brilliant but ok and you can always recharge in the car, and then enter the co-ords in to the Garmin to keep you going.

Many thanks for all the enlightening contributions from people clearly more knowledgeable than the one who started the thread. It was interesting to read all the explanations and thank you for giving us the benefit of all your experience. The flat earth approach appealed to me - it makes things much simpler. And thanks to Neil for the link to the OS website - I'm certainly a bit wiser for reading it - excellent stuff for us amateur cartographers and navigators. The Forester's post was really good, full of fascinating info. I am grateful to Mcwomble for proving my cache isn't impossible to find. The reference to Everest is of course next to useless and tongue in cheek. I thought the Essex Everest cache might not be so difficult and that people would simply do the reverse of what I did when I set it: enter the co-ordinates of each reference point and then locate the position where the GPS shows all the given distances. As a lot of people have Garmins that would measure the same way as mine I thought it might make it fairly straightforward and get round the problem and different methods of measuring accurately over long distances. But then it's simple when you know where the cache is hidden!

Thanks for your comments, much appreciated. Entering the co-ordinates as Master Mariner suggested gave me the 7,345km figure - I assume the geodesic measurement is the same as the "great circle" (the shortest distance on the earth's surface between two points)? I now know exactly what a rhumb line is thanks to Master Mariner and Wikipedia - "a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. On a plane surface this would be the shortest distance between two points. Over longer distances and/or at higher latitudes great circle routes provide the shortest distances. However the inconvenience of having to continuously change bearings while travelling a great circle route makes rhumb line navigation appealing in certain instances". Also I hadn't thought about Moote's point about local datums - it would be interesting to know exactly how Google created their maps.

I've been setting a series of caches called "Mercator Projections" which involves projecting and measuring from distant reference points to locate the cache. My latest one uses Everest, Ben Nevis and Snowden to locate a micro in Essex (some say I may have gone a bit too far on this one!). The distances using my Garmin etrex Summit HC vary from those measured using Google Earth on all 3 references point by 0.11% (Google Earth gives a shorter distance). This translates to distances of 400m to 8,000m and could make locating a cache almost impossible. I would have half expected the distances to be virtually identicial as I assume both the Garmin and Google Earth use the WGS84 datum, but would not expect Google Earth to be spot on due to the angle of the view from the satellite perhaps. It was the consistent variance I didn't understand and that suggests there is an underlying reason for it that some techie might be able to explain. I enjoy maps and working with the GPS but am no expert. Thanks in advance for any ideas. And yes before anyone says it, it may be a bit of nerdy topic and I probably need to get out more.