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Failure Of Newbie


pcassel
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Also remember: the GPSr is only accurate to about 3-10 feet of your current location (depending on the unit and the Unit's reception).

Uh, oh. If you really meant feet instead of meters, you are in for some unsuccessful and disappointing searches. Besides that, 10 to 30 meters is not a typical range of "accuracy" of a GPSr; It's a typical range of EPE, a very different animal that can easily double the size of the search area.

 

Don't forget also that you are searching for an object that, subject to the same uncertainty, was placed some unknown distance and direction from the true location of the published coordinates.

 

edit: typo

Eeep!! :(

 

I meant meters.. oopsie!!! ;)<_<

 

What's EPE and how is it different from accuracy???

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What's EPE and how is it different from accuracy???
I'm not sure there is a technical definition of accuracy. It isn't really a term that's used in purely technical documents. The generally accepted definition of accuracy would be the guaranteed maximum error of a measurement. In complex systems where there are a large number of variables affecting "accuracy" there is a statistical element to the measurement. That means that there is some very small probability that a gps will tell you you’re several miles from your known position even when you have an EPE of 30 ft. This has actually happened to me.

 

On to EPE. It stands for Estimated Positional Error. It is the radius of a circle centered on the reported position within which the unit estimates there is X probability that the unit really is. Unfortunately, I've never heard of any manufacturer divulging what X is for any consumer unit. Consensus is that X = 50%. That means that if you have an EPE of 20 ft that the unit estimates there is a 50% chance you are within twenty feet of where the unit says you are.

 

But there’s another twist. The “accuracy” (or lack of it) of the GPS system resides entirely outside the receiver, in such things as the clocks on board the satellites and in the conditions of the ionosphere between the satellites and the receiver. All the assumptions about these things were made when the software for the unit was designed and frozen in place when the software was released. Since then, at least one thing has changed: The clocks on the satellites being launched now are better than those in the originals. As time goes on the chances are getting better that any given fix is based entirely on these better clocks and therefore the positional fix is better than the unit thinks it is.

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And what's the Morale of this story???

 

#1: Some days we all suck at GeoCaching

Oh yes. It's like golf (I don't play, but I know people with a 6 handicap who can shoot 100 on a bad day; it's like their house burned down). Or chess - that I do play, to a good standard too, but some days you make a beginner's error and lost in 12 moves.

 

The other day, my brother-in-law and his g/f were over, my wife and I took them GCing. First cache: trail snowed under, DNF. Second cache: turned out to be an offset some way away, we were afraid it too would be under snow, DNF. Third cache: simple traditional, identified hiding spot easily from spoiler photo, cache is ammo box under tree trunk, 45 minutes searching with 4 of us, nada, DNF. 0 for 3. We felt like idiots. And... brother-in-law and g/f couldn't stop saying what a fantastic day out they'd had.

 

(Next day, we were 4 for 4, several easy caches, and they complained about their sore feet. No rhyme or reason to it...)

 

Nick

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OK, I went out with my daughter again last evening just before dark. We did find something, but I don't know if it was a cache. I don't want to give a spoiler, so I'll just say that it was clearly artificial and a type of marker, but it wasn't a cache of goods. I was looking for something which would contain a notebook for logging and this clearly wasn't such a thing. Anyway, I'm going to call it a Find as I think we did find it.

You really think you found it? The cache has a log book...maybe a tiny one, but something you could write on.

 

(So it will be a container of some sort, not a marker.)

 

I wish you luck in your continuing searches, but I really think this is still a DNF. ;)

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The most common novice error is relying too much on their GPS and trying to get to where the GPS reads single digits. Even if you do, you have to remember that your GPS has an EPE (estimated position error) of 15-25 feet and so did the GPS of the person who placed it. So even if your GPS reads 1 ft, the cache could be as many as 50 feet away (and sometimes more under certain conditions).

 

Also, if its a 1 star cache it should be an easy find. So either its misrated (it happens), or it is possible that the cache was stolen.

Your dead right BS! :huh: My gf still insists on getting the gps to 1'. I usually try to get within 30' then look for things that seem out of the ordinary. Thats why I find far more than her. She just doesn't get it! :lol:

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I knoticed that you have 2 finds. Have you worked out your problem now?

Just a note to anyone having the same problem and looking ofr answers. Be sure you are set to the WGS84 map datum. Mine got reset by the tiny fingers in my family to some other datum and for a couple of days I had 100% no finds. Not to mention I found myself looking in places that had no way of supporting a cache. It was VERY frustrating to say the least.

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You really think you found it?  The cache has a log book...maybe a tiny one, but something you could write on.

 

(So it will be a container of some sort, not a marker.)

 

I wish you luck in your continuing searches, but I really think this is still a DNF.    :rolleyes:

I agree with beejay&esskay.

 

The description of "A Median of Paradise" says:

"Original Contents:

* 7 Beads (2 are Cloisonné)

* Log (Please bring a pen)"

 

I hope pcassel gains some experience (and tries some "regular" sized caches) and then tries this one again.

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