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OnTheKatwalk

Conflicting coordinates

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My son and i have just placed our first cache. I  wrote down the co-ordinates of where we were from the app, then went to the nearest other cache for my son to find... And then re-traced our steps by following the co-ordinates I'd written down. They took us 20 metres from the actual GZ. So I've written down the alternate co-ordinates that the app THEN said we were at. Which should I put when submitting the cache???

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Find an app that does coordinate averaging. Or make several trips like you have done, then manually average the coordinates you obtained on those several trips.

Better practice is to allow the phone to sit at the location for a minute or two before recording those coordinates.

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Posted (edited)
22 minutes ago, K13 said:

Find an app that does coordinate averaging. Or make several trips like you have done, then manually average the coordinates you obtained on those several trips.

Better practice is to allow the phone to sit at the location for a minute or two before recording those coordinates.

 

+1

 

I've hidden all my caches with a Garmin Oregon GPS, by capturing a few dozen waypoints and then selecting one that seems most consistently close to the cache.  Not by "averaging", although that could work, too.  Before submitting the cache, I return a couple of times anyway, so I can be pretty confident that my point is good.  As K13 said, often just hanging out and looking at the coordinates, you see them settle down to a decent spot.

 

But for a phone App, I've noticed I can't quickly grab a bunch of manual waypoints.  iPhone and Android App Stores each have an App called "GPS Averaging" that displays coordinates in convenient Geocaching format.  They take many coordinate readings to create an average, and I'd supposed the spurious readings aren't part of the calculation.  The one for Android also works with Locus Maps Pro!  Both "GPS Averaging" Apps seem OK when compared to a handheld GPS, good enough for a cache if I had no handheld hiking GPS.  But serious "Averaging" requires returning at various times of day in various weather conditions, over at least a few days.  People may arrive to hunt that cache any time of year, might as well get it as close as you can, and have good hints if there seems to be an issue.  And if you get a lot of "Coords are off" logs on your caches, your plan may need work. :)

 

 

Edited by kunarion
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AND, thanks for caring about this.

 

Many new Cache Owners just walk up to GZ, write down the coordinates they see and away they go!

 

It's important to acknowledge the issues of GPS accuracy. Those satellites hang out between 12 & 13 thousand miles up, so the ones that are feeding your position could be as far as 20,000 miles away (off to the side)!!!

 

AND, they're MOVING!

 

AND, you're probably getting bounced echoes as well!

 

AND, if you're using a phone set to multi-source positioning, then that all gets magnified!

 

It's just not reasonable to expect the readings to be spot-on on a moment's notice.

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Thank you. Will return later and get a few more readings for a better average. Many thanks. All new to this :)

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Posted (edited)
1 hour ago, OnTheKatwalk said:

Which should I put when submitting the cache???

 

None of these two measurements is valid. Keep finding the GZ again and again until the offset is not more than 3 meters every time. Then you have accurate coordinates.

 

Edited by arisoft
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Phones are not the greatest GPS for geocaching, although not all apps are created equal. Some are better, and some are much worse.

 

Everyone should get an idea of how well their phone or GPS actually works.

 

Pick a convenient spot that you pass by at least daily. Just outside your front door, perhaps. Something you can precisely get back to each time. Mark a way point. Then the next time you think about it mark another waypoint. Then over a week mark waypoints on each day at whatever time you pass by. When you compare the waypoints you should get a good idea of how accurate your waypoints are.

 

With an actual GPS, I recommend clearing the track log, putting the GPS somewhere that it has a good view of the sky, and starting a fresh track log. Let it run for as long as the batteries hold up.

 

A GPS, including the one in you phone, is a navigation device intended to get you to some destination. It is not a tracking device. You should always keep this in mind when hiding or searching for a geocache.

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