When Placing a Cache The COORDINATES Should Be Close

[+The Yinnies]

I have been findind caches that are up to 30 yards away from where my GPS takes me. Is this right? Last weekend we had 4 GPS's and they all took us to a spot and the cache was a good 25 yards away. If this is how it is supposed to be that is fine but I thought when you placed them you were to take the coordinates from that spot?

[+webscouter.]

Yep, coordinates should be as close as you can make them.

[TermiteHunter]

No thats not the norm.

I'm curious how you manage to find them at a 75' + distance from the coords. 25' -30' seems to be the max distance for common error and that usually prompts a lot of DNF or "far off coordinate" logs.

[+The Yinnies]

Im sorry I mean feet.

[+TEAM HARTSOCK]

Most useful information from a GPS when geocaching.....distance to target & margin of error reading.

[+StarBrand]

The general accuracy of our handheld units is around 20 - 25 feet. Add the hiders possible error and the finders error and you could easily be searching 50 feet from the cache. 75 foot seems a bit long to me but not beyond the realm of passible error. Of course most caches are found much closer to the 20 foot range. While we strive to get the best possible coordinates, it is occasionally possible to get an error reading that send finders too far away.

[8ball9ball]

30 ft would be a normal range depending upon the margin of error between the hiders gps and yours on any given day. Most of mine have been well under that. With few exceptions you can guess, by looking at the environment, where it might be hidden. I have only had a couple that were at approx 42 ft from what my gps said was GZ. Only one that read 46 ft. That very well could have been weather, tree canopy or very possibly because they moved to an open spot to get a good reading. Basically, get close to target and look around. If your gps always put you on top of the target where would the fun or challenge be?

[+briansnat]

30 feet off is perfectly normal. Anything under 20 feet is really good. As others mentioned, GPS units don't have pinpoint accuracy, so even though the reading is taken at the cache site it can be off 10-30 feet (even more in poor conditions).

 

On top of that your unit also has a degree of inaccuracy, so worst case the cache can be 60+ feet from where your GPS says it is. I think most of the time you'll find it about 20 or so feet off though.

 

I see this as a good thing. Where would the fun be if your GPS put you dead on the cache every time?

[+Wild Thing 73]

Once your unit is showing about 60' to GZ, start looking for likely places that you might hide a cache or you think it would be a likely place, then start really looking for the container. On "micros", it is the same technique. I have noticed that most of the coordinates today are either "dead on " or very close....There are many reasons for coordinates to be off...just one is, cache owner transposes number in error ( this has happened to me and I'm sure to other cache owners )...As for as how close should the coordinates be. That answer was covered very well above. Good Luck

[+trainlove]

If you suffer from the horrible, but non-contageous, afliction of being a Magellan user, and you have not figured out it's firmware issues then you can be 100 or more feet away from a cache and your GPS might say you are right there.

 

My cure, temporary until you remove the source of infection, is detailed in http://ray.jerome.jobs.googlepages.com/gpshints

 

By the way, that disease is known as Rubberbanding.

 

In your case it seems that it's most likely you and not all the caches you find. After all, Occam's razor does apply here too.

[+ryanjrgong]

Also there is an issue in the seasons and the GPS satalites. One season they will be dead on. 5 months later they will be 30-40 feet off

[Neos2]

You don't say what kind of gps units you were using, but some are better than others in some situations. For instance, many gps units don't get good reception in heavily wooded areas or in places near a lot of tall buildings. The approach you use can make a difference, also. If you come in from the blocked signal side and the hider came in from the clear side, the coords you get can vary from theirs.

 

You could have happened upon a time when there was poor satellite reception. If there were few signals to pick up just then, it could have the reading off on all four units even if they were four top of the line highly accurate models. Had you come to look even a half an hour later, it might have made a world of difference.

 

If the cache is very old, the technology used to hide the cache might not be up to the same capabilities of today's gps units. (Although most cache hiders have gone back and fixed those hides by now with their newer gps equipment).

 

If you did a puzzle or a multi, there is a chance someone was a bit off on their math or the sign or whatever has changed since the cache was placed.

 

Some other cacher may have moved the cache a bit. Some caches just seem to wander over time.

 

Are there other logs that mention the coords being a bit off?

 

If I see no other mentions in the logs of coords being off, I usually just think it was bad satellites right then and go on about my business. Otherwise, I might say "My gps must have been a little off, but I found the cache anyway"

 

If the hint or description doesn't match the place we found the cache, I usually email the cache owner to let them know more specific info--Who was with me, what kind of gps units we had, what readings we got, exactly where we found the cache. I try to use a tone that says something like "it might have been us that were off, but we just wanted to be sure to let you know in case you think it needs to be checked?" because more than likely someone has moved the cache after it was placed.

[+Buggheart]

Also there is an issue in the seasons and the GPS satalites. One season they will be dead on. 5 months later they will be 30-40 feet off

 

I sure can relate to that statement. My GPS has been really quite accurate but when I was out yesterday it was way off and so was my mom's. I went to a cache she had already found and she was watching me find it on my own and I was walking away from it. My GPS said it was 18 feet SE but it was actually 18 NE. It was weird. Someone told us it could have something to do with wet leaves on the ground, but I'm not sure if he was playing a newbie joke on us or if there is any truth to that.

[walkguru]

some of my finds are spot on and some are way off.

[+The Yinnies]

You don't say what kind of gps units you were using, but some are better than others in some situations. For instance, many gps units don't get good reception in heavily wooded areas or in places near a lot of tall buildings. The approach you use can make a difference, also. If you come in from the blocked signal side and the hider came in from the clear side, the coords you get can vary from theirs.

 

You could have happened upon a time when there was poor satellite reception. If there were few signals to pick up just then, it could have the reading off on all four units even if they were four top of the line highly accurate models. Had you come to look even a half an hour later, it might have made a world of difference.

 

If the cache is very old, the technology used to hide the cache might not be up to the same capabilities of today's gps units. (Although most cache hiders have gone back and fixed those hides by now with their newer gps equipment).

 

If you did a puzzle or a multi, there is a chance someone was a bit off on their math or the sign or whatever has changed since the cache was placed.

 

Some other cacher may have moved the cache a bit. Some caches just seem to wander over time.

 

Are there other logs that mention the coords being a bit off?

 

If I see no other mentions in the logs of coords being off, I usually just think it was bad satellites right then and go on about my business. Otherwise, I might say "My gps must have been a little off, but I found the cache anyway"

 

If the hint or description doesn't match the place we found the cache, I usually email the cache owner to let them know more specific info--Who was with me, what kind of gps units we had, what readings we got, exactly where we found the cache. I try to use a tone that says something like "it might have been us that were off, but we just wanted to be sure to let you know in case you think it needs to be checked?" because more than likely someone has moved the cache after it was placed.

We had a Garmin Vista Hcx, Legend CX, Oregon 300 and a megellan 500. They were all off on 2 caches. One was in a wooded area and the other was wide open.

[+trainlove]

We had a Garmin Vista Hcx, Legend CX, Oregon 300 and a megellan 500. They were all off on 2 caches. One was in a wooded area and the other was wide open.

 

I guess in this previous post I should also have said the cache hider in addition to you, but if all the caches you find are off in the same direction then it is YOU. Look at my web page http://ray.jerome.jobs.googlepages.com/gpshints to help solve the problem you might be having.

 

In your case it seems that it's most likely you and not all the caches you find. After all, Occam's razor does apply here too.

[+Renegade Knight]

Im sorry I mean feet.

25' is no big deal.

 

Your GPS is 10-20' off.

Their GPS is 10-20' off. Thats if everthing is working like it should.

 

The average you will find will be about 15-20* it seems. (Based on observatons). However the normal range you will see will be from 0' to 40'. Ourtside that range it's time to wonder if the coords are off.

 

*Tree cover can make this worse.

Edited November 20, 2008 by Renegade Knight

[+delphic]

On big runs with lots of caching in the same area it is possible to make note of the direction of error. WAAS technology does a good job of correcting for atmospheric distortion but there are other factors (as mentioned above) that can cause problems. Typically, if you notice that you are 25' NE of caches on a given day, you can make corrections. An hour later, sats. might rise higher and more sats. will break above the horizon and put you right on. Just being aware of the limitations of GPS technology will make YOU more accurate.