How many feet can a coordinate differ?

[+GEO-BREIN]

I thought I once found this one in the guidelines, but now I want to find it again, I can't.

 

My question is the following: how many feet can/may a coordinate differ from the actual coordinates???

I know you have to measure the exact coordinates and all of my geocaches had/have the exact coords, but on another forum we're talking about the differ of a coordinate.

I once thought they could be with a max. difference of approximately 82ft (25m) but I can't find it anywhere.

Does somebody know this? Thanks in advance.

[jholly]

I thought I once found this one in the guidelines, but now I want to find it again, I can't.

 

My question is the following: how many feet can/may a coordinate differ from the actual coordinates???

I know you have to measure the exact coordinates and all of my geocaches had/have the exact coords, but on another forum we're talking about the differ of a coordinate.

I once thought they could be with a max. difference of approximately 82ft (25m) but I can't find it anywhere.

Does somebody know this? Thanks in advance.

If you place a traditional 82 ft from the posted coordinates your going to get a lot of angry logs.

[+K13]

You should always use the most accurate set of coordinates. Why would you want to use incorrect coordinates? .001 of a minute is around 6 feet in my part of the world. Errors over .005 (30 feet) usually cause comments in logs, so I could see LOTS of complaints if it were 80+ feet off.

[+ras_oscar]

If you were to lay an imaginary GPS grid on the earth at sea level, at the resolution we use, you would get a grid with sides of approximately 6' x 8'. However, GPS signals are never perfect, and the same GPS at the same location on different days (with different satellite constellations) will give different coordinates. I usually plan to search a circle with a 20' radius originating at the posted coordinates.

[+Semper Questio]

Actually, the Guidelines Section II.1.1 state....

 

"Listings must contain accurate GPS coordinates.

 

You must visit the cache location and obtain the coordinates with a GPS device. GPS usage is an integral and essential element of both hiding and seeking caches and must be demonstrated for all cache submissions. Projecting waypoints from a specific location already defined by set of coordinates is permissible. For geocaches that include additional waypoints see the guidelines specific to those cache types."

 

(Emphasis is mine.)

[+wmpastor]

You should always use the most accurate set of coordinates. Why would you want to use incorrect coordinates? .001 of a minute is around 6 feet in my part of the world. Errors over .005 (30 feet) usually cause comments in logs, so I could see LOTS of complaints if it were 80+ feet off.

The OP is thinking about posting coordinates off by 80 feet on purpose??

 

#1: Why??

#2: How would the OP feel in that situation when seeking a cache??

[7rxc]

It's possible the OP saw something from years back. My first 'state of the art' GPS would only give coordinates to two decimal points. With UTM display you could get a bit finer, but not much.

 

Even when they turned off SA that limited things... that .001 = 6ft was accordingly .01 = 60.

GPS was limited to map equivalent accuracy for civilians . you could estimate closer... but it was also much slower and high sensitivity receivers NOT around yet... I still use the old rig for rough work and in the car.

 

EPE's were higher for both placer and finder as well. Multi path and tree cover / canyon effects were quite limiting as well... Still found caches then. Fun to go back to the older GPS for the experience if you can find one that works... oh wait most of those still function unless damaged or fried.

 

Doug 7rxc

[+GEO-BREIN]

It is totally not the meaning to place geocaches with bad coordinates. It's just that we're talking about this matter on a different forum and I thought that I once found some more info about that in the guidelines of GS. I could swear that I once read something in the guidelines about a difference of 80ft. Of course that is a lot and personally I would not be happy when I had to search in a radius of 80ft, but that's not the point.

The point is that I thought I read something in the past in the guidelines about it, but now there's just said that the coordinates have to be as accurate as possible. And again, personally I find this the right way of course.

Guidelines change every day (in a matter of speak).

[+Kalkendotters]

I cannot remember the guidelines saying anything about coordinates being allowed to be 'off'.

In the version from 2003 it even says the coordinates should be 'exact': "The coordinates listed on the traditional cache page are the exact location of the cache."

http://web.archive.org/web/20031206082724/http://www.geocaching.com/about/guidelines.aspx

This is later changed to 'accurate' since a consumer GPS can not get exact coordinates

 

As a current GPS can get a coordinate to be accurate to about 3m (with a little time and averaging) I would say that anything more than 5m off would be really in for negative logs about the coordinates, and sometimes even 'Needs Archiving' logs.

[+GEO-BREIN]

As a current GPS can get a coordinate to be accurate to about 3m (with a little time and averaging) I would say that anything more than 5m off would be really in for negative logs about the coordinates, and sometimes even 'Needs Archiving' logs.

Make that even 1m. With my Oregon600 I can average a coordinate 'till 1m accurate. A lot of people do brag about it.

[4wheelin_fool]

Accuracy more than 30 feet off is unacceptable in most cases. In spots where there is only a narrow view of the sky, such as in a deep canyon or between tall buildings, accuracy could be much less, such as 80 -100 feet. It depends on the number of satellites and signal strength.

[+dprovan]

how many feet can/may a coordinate differ from the actual coordinates???

Zero, so make sure to be accurate or a mob will come after you.

[+Reardon41]

Around here 20 feet is usually considered acceptable for difference in conditions and units. I would never intentionally place a cache anywhere other than the best coordinates you can get with a GPSr.

[+GEO-BREIN]

I have knowledge of geocaches here in Belgium where we have to search in a radius of 10m. It's even said in the listing. A 10m radius is even more than enough to search in. Not to say undoable in most circumstances.

[+niraD]

There is no hard and fast number. As others have indicated, the coordinates should be as accurate as you can get them. If you can get them accurate to 10ft/3m (the best accuracy of most consumer GPS receivers), then do that. If you're in an area with bad reception (e.g., steep rocky canyons with heavy tree cover, or "urban canyons" with multipath issues), then do your best, and consider providing a hint to help seekers find GZ.

 

I've found caches in steep canyons with heavy tree cover where the owners couldn't get good GPS reception. They provided the best coordinates they could, and also provided other hints and clues to help seekers find GZ. That's fine; you do the best you can.

 

But deliberately bad coordinates just cause seekers to search the wrong location, growing more and more frustrated, and often growing more and more destructive.

[+NeverSummer]

If you're placing a cache and unsure if the EPE you had on your GPS will equal a good coordinate set, hunt your own cache.

 

Take your reading (average it if your GPS has that feature), and then leave the area and come back. Hunt from 0.10 miles away, and see what you find for error (distance from actual location of cache). Then, hunt again from even further away and see what you get.

 

"Beta" testing is always a good idea if you can't get a good accuracy when taking coordinates. You want your coordinates to be as accurate as possible. If for some reason you can't get coordinates you are happy with, come back later and try again.

 

At a minimum, if you think there might be an issue with the accuracy of your coordinates, be sure to clearly describe the issue, and put a good hint in the description or hint section of your cache listing.

 

As others have said, deliberate "soft" coordinates are against the guidelines, and can result in your cache being archived by a reviewer. Add in that bad coordinates with no hints or other description will result in many disappointed (and some angry) geocacachers.

 

Get comfortable with the idea that others will provide better coordinates if they can. This means that you should be prepared to change the coordinates to reflect the better ones, or ask a Reviewer to help.

Edited January 9, 2014 by NeverSummer

[+Harry Dolphin]

Get comfortable with the idea that others will provide better coordinates if they can. This means that you should be prepared to change the coordinates to reflect the better ones, or ask a Reviewer to help.

 

Ah! Like this one? Museum Hide & Seek

Coords are for the nearest street. About 147' off. Corrected coords have been listed, but the CO has made no correction.

[+TriciaG]

I'd be communicating with a reviewer about that one. We found one that was about 30 m off; the CO couldn't be bothered to fix them, saying she wasn't in the area. I talked with a reviewer; the coords got fixed.

[+NeverSummer]

Get comfortable with the idea that others will provide better coordinates if they can. This means that you should be prepared to change the coordinates to reflect the better ones, or ask a Reviewer to help.

 

Ah! Like this one? Museum Hide & Seek

Coords are for the nearest street. About 147' off. Corrected coords have been listed, but the CO has made no correction.

That's precisely why I mentioned it...well, not the cache, but the situation!

 

Someone told me exactly that little bit of advice before I hid my first cache. I'm guessing many folks aren't as lucky with good mentors or supportive communities, and don't think they need to change anything.

 

That's when we get to add more work to the Reviewer's load...and I'm not even sure how it falls under their responsibilities post-publication. Any official guidance on that process, Reviewers in our midst?

Edited January 10, 2014 by NeverSummer

[+wmpastor]

As a current GPS can get a coordinate to be accurate to about 3m (with a little time and averaging) I would say that anything more than 5m off would be really in for negative logs about the coordinates, and sometimes even 'Needs Archiving' logs.

Make that even 1m. With my Oregon600 I can average a coordinate 'till 1m accurate. A lot of people do brag about it.

As you just did!

[+NYPaddleCacher]

I'd be communicating with a reviewer about that one. We found one that was about 30 m off; the CO couldn't be bothered to fix them, saying she wasn't in the area. I talked with a reviewer; the coords got fixed.

 

There was a cache about .25 of a mile from me that was in a gorge with a stone trail along a creek. There are several waterfalls near it that are 50-80 feet high. When I found the cache the best accuracy I could get with my GPS (Garmin 76Cx) was 95 feet. Fortunately, it was an ammo can hidden in a fairly obvious spot next to the trail. I have a cache that the coordinates could be off by 50' and it really wouldn't matter. It's in a tree, the only tree, in a field with no other place (unless I just dropped it in the field) that one might think of looking within 150 feet. Sometimes the coordinates can be off and still be "good enough" but as long as a CO makes an attempt to get the most accurate coordinates possible (and uses a device with reasonable accuracy) that's about we can ask for.

 

 

[+NYPaddleCacher]

As a current GPS can get a coordinate to be accurate to about 3m (with a little time and averaging) I would say that anything more than 5m off would be really in for negative logs about the coordinates, and sometimes even 'Needs Archiving' logs.

Make that even 1m. With my Oregon600 I can average a coordinate 'till 1m accurate. A lot of people do brag about it.

 

Your GPS is telling you that it's 1m accurate. That doesn't mean that the cache is within 1m of that exact coordinates. As someone else pointed out, the difference between 42 23.001 and 42 23.002 will be 6-8 feet.

[+TriciaG]

Sometimes the coordinates can be off and still be "good enough" but as long as a CO makes an attempt to get the most accurate coordinates possible (and uses a device with reasonable accuracy) that's about we can ask for.

Yes, and in your examples, I agree that they're "good enough." But urban (no skyscrapers nearby) caches? And when 3 or 4 finders post more accurate coordinates, it shouldn't be too hard to make the coordinates on the cache page a little more accurate.

Edited January 10, 2014 by TriciaG

[+fizzymagic]

I have knowledge of geocaches here in Belgium where we have to search in a radius of 10m. It's even said in the listing. A 10m radius is even more than enough to search in. Not to say undoable in most circumstances.

 

Are those coordinates intentionally inaccurate, or are they a result of poor GPS reception? If the former, then GC numbers, please, so I can add them to my bookmark list of caches with intentionally bad coordinates.

[+hukilaulau]

To answer your question:

I think what you remember is something from the forums, not the guidelines.

There was a long discussion about how far off the posted coordinates your gps might send you. There was general agreement that a 40 foot deviation was not out of line for a single gps. So, if the hider's gps was 40 feet off, and the finder's gps was 40 feet off in another direction, the total discrepancy could reasonably be 80 feet.

Then someone came along (Fizzy?) and provided evidence complete with 8 by 10 photographs with circles and arrows on the back of each one explaining what each one was... No! Wait! That was Arlo Guthrie...

Anyway... I think that's where you remember "80 feet" from.

Now back to the off topic discussions...

[+-CJ-]

Remember there always will be people who will say you provided poor/inaccurate coordinates for your cache. This doesn't depend on any GPS accuracy. It's inside someone's heads We've got one guy here that used to announce that COs coordinates are poor and give his own coordinates as the perfect variant. In last two cases (urban caches) the difference was 9m and 7m. The background is that the guy has often complained in public about this or that cache being published "improperly": poor coordinates, vague hints, titles too long, descriptions formatted in some bad way, additional waypoints missing, inaccurate difficulty and/or terrain levels, etc. He appears to be a "cache cop" as people often call these individuals around here. So, if the OP question is related to such story of criticism I would suggest considering the described scenario.

 

When someone announces online that "my kung-fu is better than yours" we typically don't know what GPS device he has nad how he used it. "Improper coordinates" may be the result of his own poor measurements.

 

And I seriously doubt that we can talk about some range to be "acceptable". Sometimes 10 metres off coordinates make me sad. In other situations 20m seem to be pretty good. (Let's say, enough to find a cache).

[+GEO-BREIN]

To answer your question:

I think what you remember is something from the forums, not the guidelines.

There was a long discussion about how far off the posted coordinates your gps might send you. There was general agreement that a 40 foot deviation was not out of line for a single gps. So, if the hider's gps was 40 feet off, and the finder's gps was 40 feet off in another direction, the total discrepancy could reasonably be 80 feet.

Then someone came along (Fizzy?) and provided evidence complete with 8 by 10 photographs with circles and arrows on the back of each one explaining what each one was... No! Wait! That was Arlo Guthrie...

Anyway... I think that's where you remember "80 feet" from.

Now back to the off topic discussions...

 

Thanks. It's indeed more likely that I read this on a forum instead of the guidelines. I'm searching and searching but can't get to find anything else then the coordinates must be as accurate as it can be. And that's more then normal!

As I said before my Garmin Oregon 600 averages coordinates that are accurate to approximately 1m. I still take several measurements (3x) and take the average of those three readings. Every time my coordinates are on the spot.Geocachers love that.

[+GEO-BREIN]

I have knowledge of geocaches here in Belgium where we have to search in a radius of 10m. It's even said in the listing. A 10m radius is even more than enough to search in. Not to say undoable in most circumstances.

 

Are those coordinates intentionally inaccurate, or are they a result of poor GPS reception? If the former, then GC numbers, please, so I can add them to my bookmark list of caches with intentionally bad coordinates.

F.e. this one but in the mean while the CO archived the cache: C.E.De Kaj-tjes reeks K5

For those who can't read Dutch I will translate the short listing:

This multicache is nothing special. This one is just to fulfill your walk on the event and maybe you can grab some litter here and there.

The difficulty is raised because the coordinates are measured rough.

And in the hint: search in a radius of 10m and 1.5m height.

[+Pahonex]

I just started placing caches and have a couple of questions. I've had a few comments/complaints about inaccurate coordinates. I'm using an iPhone6 GPS to measure cords and then comparing to Google Maps. In some cases I'm right on, in other up to 15" +/- off. I'm reading/getting different opinions about the accuracy of both iPhones and Google Maps. Others have said just buy a "real GPS". I have a Garmin that is made for a car. Can it be used?

 

I also recently found a cache for which the listed coordinates seemed to be quite far off from the actual location. Google maps clearly shows the location in the street while the actual location is about 20' away behind the parkway and sidewalk. I've noticed this same thing on other caches by this hider. I don't really want to call the hider out in the comments but is it considered rude to send them a PM asking them to check the coordinates? I've also seen some caches that allow cache finders to submit their own corrected coordinates. What is the purpose of this? If you think your coordinates are off, shouldn't you just fix them?

[+cerberus1]

I think 20' is acceptable accuracy for civilian GPS.

When/if I get that close, the GPSrs put away anyway.

[+cerberus1]

I understand that many want to believe that their new whizzBang gps is accurate to a spiderhair.

- And 20' off from a person with a spankin' new anything having gps capability might think that "other" person's off.

 

If I remember correctly, if both hider and finder's gps is having a perfect day (which rarely, if ever happens), 10' difference is GZ.

[+niraD]

I have a Garmin that is made for a car. Can it be used?

I've never used an automotive GPS device, but my understanding is that the main challenges for using one for geocaching are battery life (they're usually plugged into the car charger) and being sure to use the off-road navigation mode (since they tend to stick to roads otherwise, which is a problem with caches that aren't along a road). Some also are set up for addresses rather than for longitude and latitude coordinates.

 

I also recently found a cache for which the listed coordinates seemed to be quite far off from the actual location. Google maps clearly shows the location in the street while the actual location is about 20' away behind the parkway and sidewalk.

Under ideal conditions, a consumer GPSr will be accurate to about 3m (10ft). That applies both to the owner's device, and to the seeker’s device, so you may find the container 5-6m (16-20ft) from ground zero under ideal conditions. Under less than ideal conditions, both GPSr readings can be much less accurate.

 

I've also seen some caches that allow cache finders to submit their own corrected coordinates. What is the purpose of this? If you think your coordinates are off, shouldn't you just fix them?

Yes, in theory, if the coordinates are off, the cache owner should just fix them.

 

In practice, not all cache owners will update the coordinates. Some are stubborn. Some are absentee. Some think "soft" coordinates makes the game more fun (not realizing that inaccurate coordinates just cause people to search more and more aggressively in the wrong location). And until the owner does update the coordinates, having better coordinates in recent logs can be useful to other seekers.

[+Viajero Perdido]

Google Maps (or -Earth) are NOT the authority. They're sometimes misaligned. GPS measurement always prevails.

 

That said, it's a good idea to check the maps anyway. If you made a major typo with the coords, it'll be obvious right away. But no fine-tuning with Google Whatever, that's just wrong.

[+jellis]

Ones I've seen 50 to 100ft off have been by badly done smartphones. And I have also seen where some cachers purposely place them coords off to make it more difficult which is not right.

[+narcissa]

Ones I've seen 50 to 100ft off have been by badly done smartphones. And I have also seen where some cachers purposely place them coords off to make it more difficult which is not right.

 

Yeah, found one a couple of weeks ago that was several hundred feet off. We only found it because previous finders mentioned the problem in the logs.

[+zookeepertx]

A couple of years ago I went looking one day for a new cache, hoping for a FTF. I never did find it and couldn't find anything that even looked like it pertained to the cache name. In fact, I nearly ended up in someone's backyard out in the country. Come to find out that the coords were off by A MILE AND A HALF!! Isn't that some kind of record?

[+Bunya]

A couple of years ago I went looking one day for a new cache, hoping for a FTF. I never did find it and couldn't find anything that even looked like it pertained to the cache name. In fact, I nearly ended up in someone's backyard out in the country. Come to find out that the coords were off by A MILE AND A HALF!! Isn't that some kind of record?

 

I think I can beat that record!

I once got an FTF on a cache where the coords were out by 187km - the placer had put E135 instead of E137.

The rest of the coords were correct and the cache name was a dead giveaway for a location only about 1km from where I lived!

[+jellis]

A couple of years ago I went looking one day for a new cache, hoping for a FTF. I never did find it and couldn't find anything that even looked like it pertained to the cache name. In fact, I nearly ended up in someone's backyard out in the country. Come to find out that the coords were off by A MILE AND A HALF!! Isn't that some kind of record?

 

I think I can beat that record!

I once got an FTF on a cache where the coords were out by 187km - the placer had put E135 instead of E137.

The rest of the coords were correct and the cache name was a dead giveaway for a location only about 1km from where I lived!

I think there is a thread about what cache had the coords the furtherest found from GZ