Geeky Question

[+nfa]

Hi,

 

what is the distance represented by a 1/1000th of a coord measurement (example: distance from 44 20.544 to 44 20.545)?

 

nfa

[+2Est8Attys]

Read Markwell's Geocaching FAQ. He has a great chart showing the distance (in feet) in 0.001 degrees. Here is the link:

Markwell's faqs

 

Edit: Is it like Markwell squared when you Markwell someone to Markwell?

Edited June 24, 2004 by 2Est8Attys

[+BeachBuddies]

It varies depending on your latitude, but near the equator it would be about 6 feet.

[+nfa]

thanks

 

nfa

[+flask]

jamie, never apologize for being geeky. stand up and be proud!

[+nfa]

I asked because a cacher couldn't find a cache I had hidden, so I went to verify that it was still there...it was/is. I took new coord readings, and they varied 5/1000ths in one direction as compared to my original listed coords.

 

I posted the revised coords, and he added a log saying that he couldn't have found the cache with the coords that far off.

 

My thinking is that the description, clues, and coords reasonably close, it should be findable (it is rated a 3.5 difficulty). I pretty much count on my GPSr reading slightly differently than the one that hid any cache I go hunting for, and also count on some variation on the same spot each time I return. I get in close, and then use the description (and sometimes the clue) to find the cache.

 

I assume that the new coords are accurate, but the actuals may be in the middle...hard to say...I've been 4 times to take coords, and they are slightly different each time (I've taken the best grouping in the middle).

 

I originally wanted to know how far off I could have been sending the cacher, and it looks like they could possibly have been looking about 23 feet off from the original coords if they used only their GPS and not the description and clues.

 

I guess that's part of the game for me, maybe not for other people...

 

nfa

[CoyoteRed]

Couldn't find the cache because the coords were 30' "off"? ~Sheesh~ try 100' or even early in our caching activity finding a cache that was 500' off! (Actually, we had forgotten the cache page and it was an offset!)

[+sTeamTraen]

I have a vague idea in my head of what 1 or 10 thousandths means, based on watching the counter click by as I walk.

 

When placing a cache, I like to walk 200 feet away and come back, do that about 4 times, and take the average.

[+Spencersb]

I posted the revised coords, and he added a log saying that he couldn't have found the cache with the coords that far off.

Sounds to me like he was just trying to "justify" his DNF!

[+flask]

jamie, some people just whine when they can't find it.

[+wrlwnd]

I have logged DNF's when I know that I did my best at the time to find. And note if I will be back to try again. if I did not look I don't log. I also don't trust the reading on my gpsr as I have seen it quite a bit off from the ones by the cache owner on the page.

 

wrlwnd

[+Marky]

I originally wanted to know how far off I could have been sending the cacher, and it looks like they could possibly have been looking about 23 feet off from the original coords if they used only their GPS and not the description and clues.

 

I guess that's part of the game for me, maybe not for other people...

 

nfa

If a cache is within 30ft of the posted coords, I am happy. If it's not, I will take an averaged reading (assuming that I have good signal and good EPE) and post it with my find log. Good descriptions and good hints are for those areas that need them (too many possible spots, bad reception, etc.). Don't worry about it too much, you did good.

 

--Marky

[+writer]

Since consumer GPS technology is only rated by definition to within 15 meters/about 50 feet in the first place, then how could you know if it was your coordinates or just the inherent inaccuracy in the system?

[+Marky]

Since consumer GPS technology is only rated by definition to within 15 meters/about 50 feet in the first place, then how could you know if it was your coordinates or just the inherent inaccuracy in the system?

With a good solid WAAS lock, I think it's more like 3 meters/10 feet. However, I'm sure you've done more research on the subject, so I may be wrong.

 

--Marky

[+Mopar]

I checked the specs on a few common consumer GPSrs and you are both correct.

GPS accuracy: Position: < 15 meters, 95% typical

WAAS accuracy:Position: < 3 meters, 95% typical

 

So even both the hider and the finder have a perfect WAAS enabled lock, they could still read 30ft apart.

If one is using something like a yellow etrex, or has WAAS off, the potential is there for 75ft difference.

I rarely even mention the coords unless they are over 50-75ft off, or by stroke of luck they are under 15ft off. 30ft is about the avg here in the North East. I did notice when I was caching in the desert out west with clear shots of the sky all the time the coords were often much better. Got kinda spoiled by every cache being within 15ft of my GPS out there.

[+trippy1976]

Read Markwell's Geocaching FAQ. He has a great chart showing the distance (in feet) in 0.001 degrees. Here is the link:

Markwell's faqs

 

Edit: Is it like Markwell squared when you Markwell someone to Markwell?

Wow! I have never seen this FAQ page but must say "THANK YOU" to Markwell for it. Absolutely awesome!