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Garmin 64 four decimal points positioning is very annoying.


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Anyway to change it back to the three decimal points that Garmin handhelds have always had?  The Setup menu apparently doesn't have an option for that.

We've had several Garmin handhelds:  eMap, two Map60, two 62s, and the 64s which came with the additional point.  It is annoying when out in the field, in the heat of summer or cold of winter, and rain on the screen to make waypoints.

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The fourth digit displayed on a GPSr is like that sweep-second hand on an alarm clock.  I mean who sets an alarm clock to 6:30:18 AM?  Besides that, that little pesky hand keeps moving!   Like every second it moves!  Very hard to determine the correct time.  Luckily, one can remove that hand and still have a very functional clock!  Who needs it! 

Sometime during the past century, people began to find the sweep-second hand useful and they reluctantly accepted the newfangled addition even though it was very confusing to use.  As a product of last century,  I too was distressed, but over time I found the sweep-second hand useful.  At least it indicates the clock hasn’t stopped working, (but a digital clock that shows hours, minutes and seconds(!) is just too pretentious for me).

Seriously, I suggest you consider the fourth digit only as an indicator how precise your GPSr calculations are given the data it receives.  The more frequent the fourth digit in the display fluctuates indicates how much ambient conditions are affecting the precision of its navigational solutions.  But, just like a digital clock displaying seconds, it does not indicate the accuracy of the display, it displays its precision at the moment.  Accuracy has its own set of problems.

Here’s an interesting article, https://blis.com/precision-matters-critical-importance-decimal-places-five-lowest-go/

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2 hours ago, Capt. Bob said:

Seriously, I suggest you consider the fourth digit only as an indicator how precise your GPSr calculations are given the data it receives.  The more frequent the fourth digit in the display fluctuates indicates how much ambient conditions are affecting the precision of its navigational solutions.

But does it really?

 

The third digit measures increments of about 6 feet (2m) or less. The fourth digit measures increments of about 7 inches (18cm) or less.

 

Consumer GPS devices are accurate to about 10ft (3m) under ideal conditions, so the third digit is likely to change every time the display updates. The fourth digit is almost certain to change every time the display updates.

 

All the fluctuating fourth digit tells you is how often your display is updating. It says nothing about the ambient conditions or your device's precision (or accuracy).

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56 minutes ago, niraD said:

Consumer GPS devices are accurate to about 10ft (3m) under ideal conditions, so the third digit is likely to change every time the display updates. The fourth digit is almost certain to change every time the display updates.

 

All the fluctuating fourth digit tells you is how often your display is updating. It says nothing about the ambient conditions or your device's precision (or accuracy).

 

Actually, no.

Since Galileo is in the air, the theoretical accuracy is less than 1 meter. As you stated, the 3rd digit had an accuracy of 2 m or less. So 3 digits simply is not enough.

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On 5/12/2022 at 5:20 PM, Atlas Cached said:

None of those models were precise enough to support the fourth digit like your new 64 is!

 

And this is all well and good but I think the additional precision makes little difference in this game.  It won't help much when I'm searching because the game uses three decimals.  It might make my cache placements slightly more accurate but I'm convinced that the error factors at the time of placement and again at time of searching will make the additional precision a moot point.   

 

My question was not about accuracy or precision or how to round to three digits or just to add zeros.  It is about the annoyance of having to deal with it when doing field puzzles.

 

I will look into the recommendation of using older firmware but that doesn't seem like a viable solution.  I assume periodic firmware updates contain important coding that I would be missing out on.

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22 hours ago, StefandD said:

Since Galileo is in the air, the theoretical accuracy is less than 1 meter.

With consumer devices?

 

Surveyors have used GPS receivers that could get get much better accuracy than 1 meter for years, but it's hardly the kind of consumer equipment that geocachers are likely to use.

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15 hours ago, niraD said:

With consumer devices?

 

Surveyors have used GPS receivers that could get get much better accuracy than 1 meter for years, but it's hardly the kind of consumer equipment that geocachers are likely to use.

Yes.

For professional use it's about 20 cm.

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4 hours ago, StefandD said:

Yes.

Do you have examples of consumer devices that actually show that kind of accuracy? The consumer equipment I found online is a little more accurate with Galileo than with GPS, but nowhere near what you're claiming.

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34 minutes ago, niraD said:

Do you have examples of consumer devices that actually show that kind of accuracy? The consumer equipment I found online is a little more accurate with Galileo than with GPS, but nowhere near what you're claiming.

https://www.deingenieur.nl/artikel/after-13-years-galileo-satellite-navigation-complete-at-last

 

Quote from the article:

Quote

The Galileo system has a greater accuracy than the current version of the American GPS. For general use, Galileo has an accuracy of less than a meter (GPS: three metres), but the high-accuracy service with encrypted signal provides position detection down to an accuracy of 20 cm.

 

 

Also: https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)

 

Quote from the article:

Quote

The Galileo system has a greater accuracy than GPS, having an accuracy of less than 1 metre (3 ft 3 in) when using broadcast ephemeris (GPS: 3 metres or 9.8 feet)[20] and a signal-in-space ranging error (SISRE) of 1.6 centimetres or 0.63 inches (GPS: 2.3 centimetres or 0.91 inches, GLONASS and BeiDou: 4–6 centimetres or 1.6–2.4 inches) when using real-time corrections for satellite orbits and clocks.

 

Edited by StefandD
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46 minutes ago, niraD said:

Do you have examples of consumer devices that actually show that kind of accuracy? The consumer equipment I found online is a little more accurate with Galileo than with GPS, but nowhere near what you're claiming.

 

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On 5/12/2022 at 6:20 PM, Atlas Cached said:

None of those models were precise enough to support the fourth digit like your new 64 is!

Excuse?  The THIRD digit in a dd mm.mmm format defines a space (at my latitude) of about 6 feet x 8 feet.  Are you claiming that the 64 is capable of an accurate fix of 0.6 feet by 0.8 feet???  If not, what is the point of displaying a 4th digit?

 

 

Edited by ecanderson
typoz
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9 minutes ago, ecanderson said:

Excuse?  The THIRD digit in a dd mm.mmm format defines a space (at my latitude) of about 6 feet x 8 feet.  Are you claiming that the 64 is capable of an accurate fix of 0.6 feet by 0.8 feet???  If not, what is the point of displaying a 4th digit?

 

 

 

This has been hashed out here and in other forums more times than I care to count.

 

There are links in this same thread with the information you seek.

 

Galileo is substantially more precise than GPS, and Garmin GPSr that use Galileo satellites are capable of calculating a position using the dd mm.mmmm format.

 

Also, please do not confuse Precision with Accuracy.

 

image.png.fecb1dcb3eafb6d64e37075ecf98ad4d.png

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24 minutes ago, Atlas Cached said:

 

This has been hashed out here and in other forums more times than I care to count.

 

There are links in this same thread with the information you seek.

 

Galileo is substantially more precise than GPS, and Garmin GPSr that use Galileo satellites are capable of calculating a position using the dd mm.mmmm format.

 

Also, please do not confuse Precision with Accuracy.

 

 

First, it wouldn't matter if Galileo could generate timing signals capable of producing a good fix to 1cm on the ground.  If the differential internal timing circuitry of the GPSr can't resolve a fix to better than 0.001 minutes, it really doesn't matter.  Moreover, the timing signals of the birds aren't the only factor in obtaining a better fix on the ground.  Even should a satellite own a timing signal good enough that the geometry could mathematically provide resolution to 1cm AGL, a MEO at 20,000+km up wouldn't actually produce a 1cm fix.  That's why ground based references are always used to get a better idea of location when a tighter fix is needed.

 

I'm not confusing precision and accuracy.  In fact, that's the whole point of the exercise.  Unless the direction and amplitude of the offset caused by a lack of accuracy in a high precision device is repeatable, the additional precision isn't of any value.

 

In short, if the 4th digit after the decimal on a Garmin consumer device doesn't provide useful information, and I'm arguing that the device itself doesn't allow for this, then there's no point in displaying it, leading the owner to believe there's a level of accuracy involved that simply doesn't exist.

 

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37 minutes ago, ecanderson said:

If the differential internal timing circuitry of the GPSr can't resolve a fix to better than 0.001 minutes, it really doesn't matter. 

 

I was always under the impression these devices reserved the timing signal from on of the in-view satellites for this very purpose. They don't need an atomic clock in the GPSr when they can just borrow it from one of the satellites overhead! 

 

 

37 minutes ago, ecanderson said:

In short, if the 4th digit after the decimal on a Garmin consumer device doesn't provide useful information, and I'm arguing that the device itself doesn't allow for this, then there's no point in displaying it, leading the owner to believe there's a level of accuracy involved that simply doesn't exist.

 

Apparently, Garmin Software and Hardware Engineers disagree with you!

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21 minutes ago, Atlas Cached said:

 

I was always under the impression these devices reserved the timing signal from on of the in-view satellites for this very purpose. They don't need an atomic clock in the GPSr when they can just borrow it from one of the satellites overhead! 

 

 

 

Apparently, Garmin Software and Hardware Engineers disagree with you!

To the latter -- Evidently!

 

As to the former... The receiver takes the satellite signals and calculates its distance from each satellite by computing the difference between the time the signal was sent from GPS satellite and the time the GPS receiver received the signal, using time data previously obtained from one of the satellites (as you say) and backing out the 'time of flight'.  Keeping accurate on-unit time derived from a satellite and the process of time differential calculation can induce errors in the result.  I haven't found that consumer devices include electronics with tolerances tight enough to produce sub-0.001 fixes ... yet.

 

Have played around a bit with selective use of the various constellations and the results have been interesting.  Not seeing a great deal of variation in results.

 

 

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8 hours ago, Atlas Cached said:

Galileo is substantially more precise than GPS, and Garmin GPSr that use Galileo satellites are capable of calculating a position using the dd mm.mmmm format.

 

But is displaying the coordinates in dd mm.mmmmm format of any use? For geocaching, all the coordinates on the website are in dd mm.mmm format and I doubt any of the other applications for a consumer-grade handheld GPSr (hiking, cycling, fishing, etc.) would require entering or reading coordinates at all (they'd be mostly reading and marking positions on the maps, I presume) and especially not in DDM format. For cachers, displaying the fourth digit means we now have to manually do the rounding that the device previously did for us automatically. How is this an end-user improvement?

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[b]Moderator Note:[/b] this basic discussion has been going on in this group for years. Garmin added it and nobody has produced a tangible reason [i]why[/i]. The precision/accuracy/digits of significance point are all facts and people that misuse them continue to misuse it.

As THIS thread is getting tiresome/personally snippy, I'm going to make one request to keep discussion here factual and away from the rude, personal, sniping that this style of posts so often turns to.

Play nice or post closed.

At least do an experiment. Paint an X on your lawn/driveway. Take the coords, as you would with a cache.  Now, daily for a few weeks, navigate to that point, as you would with a cache, and see if that last digit is immutable.

My assumption is that it's noise, but it at least covers something beyond the same tired ground...

But at the very least: play nice and let's not have the same eternal thread.

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28 minutes ago, robertlipe said:

At least do an experiment. Paint an X on your lawn/driveway. Take the coords, as you would with a cache.  Now, daily for a few weeks, navigate to that point, as you would with a cache, and see if that last digit is immutable.

 

I did that a few years back in another thread on this topic, using the corner of a bench seat on the local beach as my reference point where there's a clear 360 degree view to the horizon. The results were as expected, the fourth digit was just noise. But even if it isn't on the newer Galileo-compatible GPSrs, there's still nothing you can do with it other than round it to the nearest 3 digits, which is what used to happen automatically when it only displayed 3 decimal digits. Having to manually round when transferring coordinates taken in the field into cache page waypoints just adds an extra opporunity for errors to creep in.

 

I guess all we can hope for is that Garmin might eventually add an option in the display formats for dd mm.mmm, after all there's already a great long list of options to chose from so adding one more shouldn't be that hard. I'm not holding my breath though.

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8 hours ago, barefootjeff said:

For cachers, displaying the fourth digit means we now have to manually do the rounding that the device previously did for us automatically. How is this an end-user improvement?

 

Frankly, how long ago you used any of these digits to find a cache? My device usually displays distance and direction.

 

When you hide a cache and use coordinate averaging the fourth digit is the result of the averaging.

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21 minutes ago, arisoft said:

Frankly, how long ago you used any of these digits to find a cache? My device usually displays distance and direction.

 

When you hide a cache and use coordinate averaging the fourth digit is the result of the averaging.

 

When doing multis I have to key coordinates in. Admittedly that's only a matter of appending zeros to the south and east, but it's still extra keystrokes that weren't previously needed. It gets trickier though when the multi or field puzzle requires you to add or subtract an offset to your present position (I own a couple like that). My main gripe is when reading coordinates off the device to enter into cache page waypoints, as regardless of how that fourth digit is obtained (Galileo, averaging, tarot cards or whatever) it still has to be manually rounded to three digits and that's when errors are likely to happen.

Edited by barefootjeff
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5 hours ago, barefootjeff said:

My main gripe is when reading coordinates off the device to enter into cache page waypoints, as regardless of how that fourth digit is obtained (Galileo, averaging, tarot cards or whatever) it still has to be manually rounded to three digits and that's when errors are likely to happen.

 

Good news! 

 

Geocaching.com is using four digits natively.

Here is what you do when creating a new cache

 

image.png.d059bdba2c71db5fb8a3842ef270c5ab.png

 

This is how the system converts it to three digits automatically for the cache description. (UTM is more precise here)

image.png.db56266ff64a2ca80061db94da0a66ec.png

 

And when you download this to your Garmin by pressing download GPX you will get

 

<wpt lat="60.267572" lon="24.861363">

 

Which is the exactly the original N60 16.0543  E24 51.6818 when rounded to 4 digits :cool:

 

Summa summarum... you have made unnecessary work by manually decreasing the precision of your coordinates. The three digit coarse precision is possible to obtain only when you enter coordinates manually from the cache description page to your gps receiver. Every App and exporting tool is using these precise coordinates without decreasing the precision.

Edited by arisoft
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8 hours ago, arisoft said:

Good news! 

 

Geocaching.com is using four digits natively.

 

Interesting, I hadn't realised the website would accept 4 decimal digits and do the rounding in a consistent manner. I just did a bit of playing with one of my mystery caches to make sure adding the extra digit wouldn't cause any problems with the inbuilt checker but it all seems to work as expected. Thanks!

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On 6/12/2022 at 9:46 PM, barefootjeff said:

manually round when transferring coordinates taken in the field into cache page waypoints just adds an extra opporunity for errors to creep in.

XXX delete above

 

On 6/13/2022 at 4:00 AM, barefootjeff said:

it still has to be manually rounded to three digits and that's when errors are likely to happen.

 

As an engineer, I know there are at least six different rounding conventions in common use in the real world. Since most of us aren't in Asia with convenient positive lats and longs, there's surely some required agreement here on the sign traits, right?  You're not standing in the woods arguing about rounding toward zero vs rounding to even or whatever, are you?

I wouldn't be surprised if there isn't an actual convention chosen here because this digit is fiction in our units anyway. Next we should all be fretting about marking up our fields with the number of significant figures, too.

 

19 hours ago, arisoft said:

Here is what you do when creating a new cache

 

This is how the system converts it to three digits automatically for the cache description. (UTM is more precise here)

image.png.db56266ff64a2ca80061db94da0a66ec.png

 

And when you download this to your Garmin by pressing download GPX you will get

 

<wpt lat="60.267572" lon="24.861363">

 

Which is the exactly the original N60 16.0543  E24 51.6818 when rounded to 4 digits :cool:

 


The "precision" of UTM is a bit of a fallacy. It has more digits, but they're imaginary also. Your GPS "thinks" in spherical data, a geographic coordinate system from WGS-84. UTM is a projection. The process of getting from a flat map to a spherical one introduces distortion at the edges. It takes some hairy code that looks about like https://gist.github.com/attilaolah/6cf22de8949d45a6cc06286536050e42 (GPSBabel's code does this using lots of smaller functions, so it's harder to point at a single block and express the horror.) The formulae to correct distortion near the page seams is reversible, but it's kind of synthetic to declare it "more precise" when it just plain takes more characters because it's encoding a region, a zone,, and a number of meters N and E within that page.

See also: https://gis.stackexchange.com/a/1328

As for your later example, you can do this within GPSBabel, too.

➜  ~ echo "N60 16.0543,  E24 51.6818"  | gpsbabel -i csv -f -
60.267572N 24.861363E WPT001/WPT001
➜  ~ echo "N60 16.0543,  E24 51.6818"  | gpsbabel -i csv -f -  -o gpx -F -
<?xml version="1.0" encoding="UTF-8"?>
<gpx version="1.0" creator="GPSBabel - https://www.gpsbabel.org" xmlns="http://www.topografix.com/GPX/1/0">
  <time>2022-06-14T09:35:23.652Z</time>
  <bounds minlat="60.267571667" minlon="24.861363333" maxlat="60.267571667" maxlon="24.861363333"/>
  <wpt lat="60.267571667" lon="24.861363333">

You can see our (my) GPX writer suffers from peer pressure on fantasy precision.


 

11 hours ago, barefootjeff said:

 

Interesting, I hadn't realised the website would accept 4 decimal digits and do the rounding in a consistent manner. 


That's a recent-ish change. It wasn't that long ago that the site had a rather more hostile input method. Jeff Boulter and I were fussing about that almost 20 years ago, back when bookmarklets roamed the earth. Geocachers Boulter and Parkerr helped add that 18 years ago and we were begging geocaching.com to implement it from our example parsing human-readable freetext coordinates.
 

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1 hour ago, robertlipe said:

Your GPS "thinks" in spherical data

 

Actually, GPS "thinks" positions in XYZ geocentric coordinates. Other coordinate systems is just a conversion from that.

 

1 hour ago, robertlipe said:

but it's kind of synthetic to declare it "more precise" when it just plain takes more characters

 

I guess that you think about accuracy. See earlier posts is this thread to see the difference between precision and accuracy.

 

1 hour ago, robertlipe said:

That's a recent-ish change.

 

For my own experience, at least 12 years ago, it was possible to enter decimal degrees for a cache position with higher precision than milliminutes. Coordinates in the database and GPX files are stored in floating point degrees. Conversion to milliminutes from this presentation is made only for human readers that are more familiar with imperial style units than decimals. ;)

 

The recent change is that you can not use decimal coordinates in the cache editor any more. It accepts only DMM now. I have no idea whether there was a limit to three decimals or not.

Edited by arisoft
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4 hours ago, Atlas Cached said:

 

You are referencing accuracy, not precision.

 

The 4th digit is all about precision, not accuracy.

I'm aware of that.  Again, we've been down this road before.

If results aren't repeatable to the 4th digit, doesn't much matter to the person using the device to locate something whether it's 3 or 4, does it?

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35 minutes ago, barefootjeff said:

 

Precision without corresponding accuracy is just meaningless digits.

That assumes that the claimed "precision" is even there. 

 

I don't really care how precise you make the display - a 4th digit isn't even cute, much less useful at this time.  It reminds me of folks who publish puzzle caches that resolve to dd.dddddd.

 

The 64 isn't going to get anyone closer to a cache for having 4 digits of precision.  I do not understand the claim that "None of those models were precise enough to support the fourth digit like your new 64 is!"  The 64 has no better repeatability to a 4th digit (precision) than others I've seen in the field.

 

Not sure why Atlas doesn't understand that repeatability is precision.  He's usually the first to get the terms right.  As long as I can hit the target in a small group, even if way off to the side, that's repeatability.  It likely also means I have a sight adjustment problem or a bad habit, but that's for another day...

 

 

Edited by ecanderson
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I agree with robertlipe and Atlas Cached!

 

Well, who am I and what did I do?  Okay, I was an aerospace engineer for a 45 year career.  As a related subject from 1995 to 2002, I worked in the Propulsion Engineering group for the Delta II launch vehicles.  We were launching, among others, the second generation GPS satellites.  If your GPS devices work successfully, I made no fatal mistakes in establishing the veracity of the launch data that we sent to the launch team at the cape.

Edited by Team CowboyPapa
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2 hours ago, Team CowboyPapa said:

I agree with robertlipe and Atlas Cached!

 

Well, who am I and what did I do?  Okay, I was an aerospace engineer for a 45 year career.  As a related subject from 1995 to 2002, I worked in the Propulsion Engineering group for the Delta II launch vehicles.  We were launching, among others, the second generation GPS satellites.  If your GPS devices work successfully, I made no fatal mistakes in establishing the veracity of the launch data that we sent to the launch team at the cape.

 

That's all well and good, and I don't know whether the fairly recent Garmin handheld consumer-grade devices are accessing the satellites you launched, but this is fairly typical of what I get in the field with my Oregon 700 (purchased in 2018).

 

WP2Spread.jpg.b0b9873d33436b700bf5524de60563aa.jpg

 

Those three flags represent coordinates I took on three separate days at the waypoint location for a new cache I'm working on. Note the scale on the map, yes that's 8 metres, not 8 centimetres. What is the point of it displaying the minutes to four decimal places (a resolution of 18cm) when the day-to-day spread is so great? The blue trace, by the way, is just from today's visit, when I took the waypoint in the lower right where it seemed to have settled, went over to another waypoint and returned an hour later, watching it meandering around well south of all my markers over the course of about half an hour.

 

I was also taking readings on my phone, a Samsung Galaxy A52 that's just over a year old, with a similar spread in coordinates. At least the phone wasn't trying to tell me it had centimetre accuracy.

 

The location shouldn't be a particularly difficult one. It's in open eucalypt forest just below the top of a hill on a fairly gentle slope, the sort you can easily walk up without raising a sweat. Here's a photo taken at the waypoint; I was standing on top of the rock (marked with an X) when taking my readings.

 

WP2Rocks.jpg.b85f692a2f9f8c89569dfc56e44d2ee7.jpg

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On 10/4/2022 at 5:24 AM, barefootjeff said:

Note the scale on the map, yes that's 8 metres, not 8 centimetres. What is the point of it displaying the minutes to four decimal places (a resolution of 18cm) when the day-to-day spread is so great?

 

Did you use averaging feature of you GPS receiver when storing these coordinates?

 

Once I forgot my GPS receiver in the woods when averaging coordinates. Next day I got it back and found that coordinates made some huge loops.

Edited by arisoft
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13 minutes ago, arisoft said:

Did you use averaging feature of you GPS receiver when storing these coordinates?

 

I manually averaged over about half an hour by watching where it was meandering and placing the marker close to the centre. I came back an hour or so later and it was consistently meandering about 7 or 8 metres south. Curiously, the first waypoint on the other side of the hill, where the ground is steeper, has been rock solid within a few metres each day I've checked.

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