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Hiding a cache - use app or gps?


DaNerdling

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Hey there, brand new cacher here. I just started caching with my girlfriend about a month ago and I really want to hide my own cache, but I'm having a couple issues getting started. When I go to log the coordinates of where I wish to hide my cache, is it more advisable to use the built-in coordinates on the app, or an actual gps device? A gps is a little out of my price range at the moment, so I was just curious how accurate the built-in coordinates are. The caches I've encountered so far, only one was dead on as far as the coordinates go, and I want my cache to be found easily (not by muggles though).

 

Any advice on how I should proceed?

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Which app? Which phone?

 

The app I use (CacheSense) can do coordinates averaging. That helps a lot, because you aren't subject to the whims of a single reading. But ultimately, any app depends on the accuracy of the GPS system that's built into your phone.

 

The last time I listed a cache, I didn't see a significant difference between the coordinates I got from my phone and my eXplorist. But the locations were generally out in the open, where the phone does well. The times when I notice a difference between the two is when I'm in an area with poor GPS reception, like a steep canyon, or under heavy redwood tree cover.

 

But if you don't trust your coordinates, then test them.

 

Enter your coordinates into your device, and then approach the cache location from at least 100ft/30m away. The arrow should point right at the cache location as you approach. Repeat the process, approaching the cache location from various directions, from at least 100ft/30m away each time. No matter which direction you approach from, the arrow should point right at the cache location.

 

If it doesn't, then adjust your coordinates until it does.

 

Bonus points for repeating the test on another day when the GPS satellites are in a different configuration.

 

Also, the Help Center article How to Get Accurate Coordinates should prove useful.

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Which app? Which phone?

 

The app I use (CacheSense) can do coordinates averaging. That helps a lot, because you aren't subject to the whims of a single reading. But ultimately, any app depends on the accuracy of the GPS system that's built into your phone.

 

The last time I listed a cache, I didn't see a significant difference between the coordinates I got from my phone and my eXplorist. But the locations were generally out in the open, where the phone does well. The times when I notice a difference between the two is when I'm in an area with poor GPS reception, like a steep canyon, or under heavy redwood tree cover.

 

But if you don't trust your coordinates, then test them.

 

Enter your coordinates into your device, and then approach the cache location from at least 100ft/30m away. The arrow should point right at the cache location as you approach. Repeat the process, approaching the cache location from various directions, from at least 100ft/30m away each time. No matter which direction you approach from, the arrow should point right at the cache location.

 

If it doesn't, then adjust your coordinates until it does.

 

Bonus points for repeating the test on another day when the GPS satellites are in a different configuration.

 

Also, the Help Center article How to Get Accurate Coordinates should prove useful.

 

I was referring to the official Geocache app for iPhone. It shows you your coordinates so I was curious if it is reliable source for hiding a cache as I want it to be as easily accessible as possible (DNF's are so disheartening). I found a free third party app as well but it proved less than reliable. I'm sure I could find a used device for relatively cheap, but I just want to make sure my cache is accurate as possible before I list it.

Edited by danerdling
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If I was gonna place caches with my phone, I'd probably add one of the many waypoint averaging apps (sometimes just called "GPS averaging"), for a little extra assurance that my coords would be as accurate as my phone provides. :)

+1 to that. I don't suppose gc.com has ever gotten around to adding that 'best practices' function to their own app code, have they?
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And just to be clear, to the OP, the accuracy of coordinates in your phone (regardless of which app you use) is dependent on your phone. Some phones are better than others. One app on your phone shouldn't be more accurate than another app on your phone, since they are both 'reading' your location based on the GPS built into your phone. I'm sure there are others that can describe the technicalities better than I can.

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Hey there, brand new cacher here. I just started caching with my girlfriend about a month ago and I really want to hide my own cache, but I'm having a couple issues getting started. When I go to log the coordinates of where I wish to hide my cache, is it more advisable to use the built-in coordinates on the app, or an actual gps device? A gps is a little out of my price range at the moment, so I was just curious how accurate the built-in coordinates are. The caches I've encountered so far, only one was dead on as far as the coordinates go, and I want my cache to be found easily (not by muggles though).

 

Any advice on how I should proceed?

 

Further to the other advice my suggestion is to make sure your phone's GPS has been working and receiving a clear signal for at least 10 minutes after getting a 'lock', before taking a reading - that way it will be likely to be receiving the maximum number of satellites, thereby maximising the accuracy.

 

If your cache is in woodland or on or near a large metal structure you will find it more difficult to get a good reading whatever GPS receiver you have, so the more accuracy you can get, the better.

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I got my coordinates today using the geocaching app, tap start on a cache, go to the compass and look where it says current location, but my phone has quite a good signal...

 

GPS/satelite signal, or from the cell service towers?

If it's from the phone/cell service towers, for the phone signal, it's not too accurate.

 

A decent set of coordinates can be gained using a phone. Just take your time, and take several readings.

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I got my coordinates today using the geocaching app, tap start on a cache, go to the compass and look where it says current location, but my phone has quite a good signal...

 

GPS/satelite signal, or from the cell service towers?

If it's from the phone/cell service towers, for the phone signal, it's not too accurate.

 

A decent set of coordinates can be gained using a phone. Just take your time, and take several readings.

 

In the US of A, cell phones are required to connect to satellites. That way, with an emergency phone call, they have your location. (Of course, it also means that they can spy on us.)

That does not mean that the coords are very accurate. Guidelines say that a GPSr should be used to get the coordinates of the hide.

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I got my coordinates today using the geocaching app, tap start on a cache, go to the compass and look where it says current location, but my phone has quite a good signal...

 

GPS/satelite signal, or from the cell service towers?

If it's from the phone/cell service towers, for the phone signal, it's not too accurate.

 

A decent set of coordinates can be gained using a phone. Just take your time, and take several readings.

 

In the US of A, cell phones are required to connect to satellites. That way, with an emergency phone call, they have your location. (Of course, it also means that they can spy on us.)

That does not mean that the coords are very accurate. Guidelines say that a GPSr should be used to get the coordinates of the hide.

 

Oh, it looks like the guidelines need to be updated...

 

I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

 

Waypoint averaging is a VERY GOOD IDEA, and smartphones are normally much much faster to get gps coords, and to do multi-sample averaging. Wether this is because of the awesome processing power or just better math, I dunno. It will be faster with a modern smartphone, and more accurate, from my experience.

 

Helpful Hints for Good Averaging:

turn off cellular /wifi data

turn off google services

turn on ONLY gps as a source for triangulation

 

then start averaging. It might take 2 minutes to get a +/- sub foot estimation, or less depending on your phone model.

 

If you don't believe it, take your phone and whichever standalone out and try it. Please do and report back, I think you'll be surprised, pleasantly.

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"Best guestimate" of 6 inches is someone having fun with their app. EPE (the number you cite) is largely a function of the imagination of the programmer when creating the algorithm. In your case, does the author even describe what he means when displaying his EPE? They're ALWAYS statistical guesses with assumptions about percentages included if done properly.

No way your cell phone or any consumer handheld is good to that level of resolution, even over an averaged time of several minutes.

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I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

I gotta agree with ecanderson.

Civilian GPS is only accurate to around 10 feet on a perfect day.

Anything else is either a fluke, or the programmer's recipe wasn't done cookin'. :)

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I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

I gotta agree with ecanderson.

Civilian GPS is only accurate to around 10 feet on a perfect day.

Anything else is either a fluke, or the programmer's recipe wasn't done cookin'. :)

 

Again the problem of precision versus accuracy. If an accuracy of ten feet exists, a precision of six inches is meaningless.

Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points. Great precision, but meaningless.

The box that's 31 x 29 x 73 is 37.98 cubic feet

Or it might be 30.5 x 29.5 x 72.5 at 36.47 cubic feet

Or it could be 31.25 x 29.25 x 73.25 at 38.75 cubic feet.

Precision without accuracy is meaningless. Okay. Your box is 37.98 cubic feet. Doesn't meana thing, but it keeps the customer happy.

If the cell phone claims to have six inches of accuracy, it is lying. Without the accuracy, it is meaningless.

Edited by Harry Dolphin
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I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

I gotta agree with ecanderson.

Civilian GPS is only accurate to around 10 feet on a perfect day.

Anything else is either a fluke, or the programmer's recipe wasn't done cookin'. :)

 

Again the problem of precision versus accuracy. If an accuracy of ten feet exists, a precision of six inches is meaningless.

Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points. Great precision, but meaningless.

The box that's 31 x 29 x 73 is 37.98 cubic feet

Or it might be 30.5 x 29.5 x 72.5 at 36.47 cubic feet

Or it could be 31.25 x 29.25 x 73.25 at 38.75 cubic feet.

Precision without accuracy is meaningless. Okay. Your box is 37.98 cubic feet. Doesn't meana thing, but it keeps the customer happy.

If the cell phone claims to have six inches of accuracy, it is lying. Without the accuracy, it is meaningless.

 

i think you're saying that averaging is meaningless ?

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I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

I gotta agree with ecanderson.

Civilian GPS is only accurate to around 10 feet on a perfect day.

Anything else is either a fluke, or the programmer's recipe wasn't done cookin'. :)

 

Again the problem of precision versus accuracy. If an accuracy of ten feet exists, a precision of six inches is meaningless.

Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points. Great precision, but meaningless.

The box that's 31 x 29 x 73 is 37.98 cubic feet

Or it might be 30.5 x 29.5 x 72.5 at 36.47 cubic feet

Or it could be 31.25 x 29.25 x 73.25 at 38.75 cubic feet.

Precision without accuracy is meaningless. Okay. Your box is 37.98 cubic feet. Doesn't meana thing, but it keeps the customer happy.

If the cell phone claims to have six inches of accuracy, it is lying. Without the accuracy, it is meaningless.

 

i think you're saying that averaging is meaningless ?

 

No. Averaging is a good idea. What I am saying is that without accuracy, precision is meaningless. If a GPSr/cell phone is accurate to ten feet. Then claiming precision to six inches meaningless.

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I got my coordinates today using the geocaching app, tap start on a cache, go to the compass and look where it says current location, but my phone has quite a good signal...

 

GPS/satelite signal, or from the cell service towers?

If it's from the phone/cell service towers, for the phone signal, it's not too accurate.

 

A decent set of coordinates can be gained using a phone. Just take your time, and take several readings.

 

In the US of A, cell phones are required to connect to satellites. That way, with an emergency phone call, they have your location. (Of course, it also means that they can spy on us.)

That does not mean that the coords are very accurate. Guidelines say that a GPSr should be used to get the coordinates of the hide.

 

Actually the current guidelines say:

"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..."

 

I suggest the term "GPS device" is used to be inclusive of smart phones.

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Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points.

Either your customers don't know how to write specs or you don't know how to make boxes. I'm betting on the former. Still, when a customer specifies a tolerance for the actual dimensions that you can't achieve in your shop, you should either get him to revise his drawings or no-bid the job.
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Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points.

Either your customers don't know how to write specs or you don't know how to make boxes. I'm betting on the former. Still, when a customer specifies a tolerance for the actual dimensions that you can't achieve in your shop, you should either get him to revise his drawings or no-bid the job.

 

You misunderstand. Customers send us freight to be packed for export. We build the box to fit the freight. We determine the size of the box. But many insist that our packing list specify the volume to two decimal points, even though that is completely useless information.

To build a box to be accurate to two decimal points would be prohibitively expensive. And that is the point here. If one wants a GPSr accurate to six inches, he would need a surveyor grade unit. Prohibitively expensive. Ten feet is the accuracy. The cited Iphone might be accurate to ten feet. The person who said it was accurate to six inches is wrong to think it is that accurate.

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Ah, I see. I thought you were building custom cardboard for someone and selling them the boxes. Yeah, dims for international shipment don't require 2 decimal places. It's about as silly as spec'ing geocache coordinates as XX.XXXXXXº when you look at what that last digit actually represents in distance. Google is funny that way, too. You can't begin to even zoom in enough to mark a point on either their map or satellite images to 0.000001 degrees, but when you mark something, that's the number of digits that they return. It's beyond the ability of any consumer grade GPS anyway.

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I've watched as a standalone garmin was left to average it's location, for over ten minutes (with my phone next to it, averaging also). It returned a probability of +/-30 feet (that's THIRTY feet, +/-), and when I picked up my phone saw a best guestimate of +/- 6 inches. SIX inches, from a smartphone. My phone is over four years old, and the garmin in question was also.

I gotta agree with ecanderson.

Civilian GPS is only accurate to around 10 feet on a perfect day.

Anything else is either a fluke, or the programmer's recipe wasn't done cookin'. :)

 

Again the problem of precision versus accuracy. If an accuracy of ten feet exists, a precision of six inches is meaningless.

Reminds me of a similar problem where I work. If we build a box, we measure to the nearest inch. Our customers insist they need the cubic feet to two decimal points. Great precision, but meaningless.

The box that's 31 x 29 x 73 is 37.98 cubic feet

Or it might be 30.5 x 29.5 x 72.5 at 36.47 cubic feet

Or it could be 31.25 x 29.25 x 73.25 at 38.75 cubic feet.

Precision without accuracy is meaningless. Okay. Your box is 37.98 cubic feet. Doesn't meana thing, but it keeps the customer happy.

If the cell phone claims to have six inches of accuracy, it is lying. Without the accuracy, it is meaningless.

 

i think you're saying that averaging is meaningless ?

 

No. Averaging is a good idea. What I am saying is that without accuracy, precision is meaningless. If a GPSr/cell phone is accurate to ten feet. Then claiming precision to six inches meaningless.

 

please go out and try averaging for yourself.

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@ohgood

 

+1 to Harry, -1 to you.

 

He's not arguing against averaging. He's arguing against a phone claiming 6" of EPE regardless of any averaging. It's a bogus artifact of some developer's way of computing that number for that app.

 

give it a try. the worst you'll find is that it works, right ?

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Thanks for all the help guys. I ended up caving and bought a Garmin Etrex 10. I currently have 7 hides out there and so far they are going over quite well. Re-reading my original post, even I'm not sure exactly what I was asking... chalk it up to inexperience I guess. But now I have just under 450 finds so I've got a little experience now ;)

 

Thread may be closed as I found my answer. Thanks again guys, I appreciate the help.

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