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Fourth decimal digit added to coordinates in recent Garmins. Was:New 66st User with a Question

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I discovered the Garmin 66st adds an extra decimal digit of precision to coordinates, such as N 46 18.2386.  Is there a way to prevent that extra fourth decimal digit from displaying?

 

Thanks!!

 

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If you do a search right here in tis forum, you will find a very long conversation about this very subject.

 

The short answer is, 'No.' Ignore the 4th digit if you do not want to use it.

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Well, you can't ignore that 4th digit completely: when entering coordinates, you have to set it to zero to get avoid being as much as 0.0009 minutes off. The more precise answer is "no, just live with it."

 

(And admittedly the question has been asked before, but I wouldn't know how to search the forums for it. At least I couldn't find the previous long discussion when I searched just now.)

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2 minutes ago, dprovan said:

At least I couldn't find the previous long discussion when I searched just now.

Don't feel bad. I couldn't find it either. In the midst of my searching for it, a reply had been posted covering everything I would have said anyway.

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HA. When google searches your forums better than your internal search function.

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4 minutes ago, Mineral2 said:

HA. When google searches your forums better than your internal search function.

 

Scary, right?

 

8^)

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5 hours ago, Atlas Cached said:

Not a thing about the 66st or anything recent. I am fascinated that "extra digit" does hit some discussion about this issue in other devices where "precision", the more accurate and concise term for what the OP was asking about, does not.

 

Anyway, we've answered here, so no need for anyone to go looking.

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5 hours ago, dprovan said:

Not a thing about the 66st or anything recent. I am fascinated that "extra digit" does hit some discussion about this issue in other devices where "precision", the more accurate and concise term for what the OP was asking about, does not.

I don't navigate to a cache with the pointer, I navigate by looking at my current location compared to the destination coordinates. I can't speak for the OP but when I posted in the last discussion on this subject precision wasn't a concern, having the GPSr display match how geocaches are normally listed was. I learned to navigate with a GPSr on a handheld that displayed UTM to at least 12 decimals, I want to say it was 14. Very precise, but when navigating to a location where someone had scribbled 11 decimals on a scrap of paper a margin of error was added. The cache page posts coordinates in three decimals, GSAK lists caches in three decimals, what is wrong with asking to have the GPSr display cache coordinates in what has become the standard for displaying cache coordinates?

 

If I drive I-19 south of Tucson the speed limit signs are posted in KPH rather than MPH. KPH to MPH and vice versa is an easy conversion done in your head but I don't have to because I can make a few pushes of a button and the speedometer display matches what is POSTED on the highway signs. I'm sure the Garmin overlords know the best way for me to navigate but when a car speedometer can do something an expensive piece of navigational equipment can't I get aggravated.

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The Galileo-System is supposed to be more precise than the GPS, as long as you’re using the „toys“ that we use for geocaching. Only the Galileo-capable units use 4 digits, the GPS/Glonass units don’t.  So the extra-digit makes sense, GARMIN is up-to-date and GC.com outdated as soon as Galileo is working properly, and that won’t take long. „Standard“ now, but I think GC.com will switch to 4 digits sooner or later, so you better get used to it.

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Posted (edited)

Since this Question is become Frquently Answered, I'm going to put it at the top to increase visibility.  I've also improved the subject line to help future seekers. This seems to be one of the better discussions:

 seems 

Edited by robertlipe
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On 8/8/2019 at 11:19 PM, Henne1312 said:

The Galileo-System is supposed to be more precise than the GPS, as long as you’re using the „toys“ that we use for geocaching. Only the Galileo-capable units use 4 digits, the GPS/Glonass units don’t.  So the extra-digit makes sense, GARMIN is up-to-date and GC.com outdated as soon as Galileo is working properly, and that won’t take long. „Standard“ now, but I think GC.com will switch to 4 digits sooner or later, so you better get used to it.

 

Curious, as I can't find anything to suggest the Oregon 700 is Galileo-capable yet it's now displaying 4 digits in the decimal minutes. The only options it shows are GPS or GPS+GLONASS.

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23 minutes ago, barefootjeff said:

 

Curious, as I can't find anything to suggest the Oregon 700 is Galileo-capable yet it's now displaying 4 digits in the decimal minutes. The only options it shows are GPS or GPS+GLONASS.

 

The Oregon 7x0 series GNSS chipset is Galileo capable, but has not yet been enabled. Contact Garmin and ask when this is going to happen.

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44 minutes ago, barefootjeff said:

 

Curious, as I can't find anything to suggest the Oregon 700 is Galileo-capable yet it's now displaying 4 digits in the decimal minutes. The only options it shows are GPS or GPS+GLONASS.

 

Me and Atlas Cached already told you that it is but not yet enabled 

 

 

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56 minutes ago, Henne1312 said:

Me and Atlas Cached already told you that it is but not yet enabled 

 

So if it's not still not enabled in firmware (and in all likelihood won't be because it would seem a pretty dumb marketing strategy to make a unit with a feature that could be attractive to buyers and then not enable it or even publicise it) then, regardless of whether its receiver chip supports Galileo, the fact is that, at the present time at least, the Oregon 700 does NOT support Galileo. I suspect if they do eventually enable it on that hardware platform, it'll be in the form of a new model version (700X ?) so they can monetize it.

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Galileo is not yet working properly, four satellites to come in 2020 and high precision supposed to be enabled this year. It’s way behind schedule, should have been working 10 years ago. So no need to enable it on the 700 now for marketing reasons only. I assume that it will be enabled when Galileo is working on high precision, but if that takes longer, maybe Garmin will introduce a new model as you suspect.

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On ‎8‎/‎8‎/‎2019 at 5:01 AM, 31BMSG said:

I learned to navigate with a GPSr on a handheld that displayed UTM to at least 12 decimals, I want to say it was 14. Very precise...

That many decimal places is certainly precise, but completely meaningless and unnecessary in this application (and nearly every other application). 12 decimal places would be measuring picometres. For reference, the estimated diameter of a hydrogen atom is 25 picometres. From Wikipedia:

Quote

The picometre's length is of an order so small that its application is almost entirely confined to particle physics, quantum physics, chemistry and acoustics.

 

I'd be skeptical if a consumer GPS receiver billed itself as being able to accurately provide measurements to the metre-level, let alone sub-metre. Certainly not to the sub-atomic level. :laughing:

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Precision and Accuracy are two entirely different animals frequently confused for each other.

 

All things being equal, the GPS radio in the GPSr may very well be 4 digit precise, but not 4 digit accurate.

 

The-concept-of-accuracy-versus-precision.thumb.png.24cd0bf71ef7bcae390278f8bba637f9.png

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15 hours ago, The A-Team said:

That many decimal places is certainly precise, but completely meaningless and unnecessary in this application (and nearly every other application). 12 decimal places would be measuring picometres. For reference, the estimated diameter of a hydrogen atom is 25 picometres. From Wikipedia:

 

I'd be skeptical if a consumer GPS receiver billed itself as being able to accurately provide measurements to the metre-level, let alone sub-metre. Certainly not to the sub-atomic level. :laughing:

I never implied that it be used in a caching application or it was a consumer item. I was merely pointing out the method I was taught in 1991 that I still use today, and that comparing a screen with 4 decimals to a page with 3 decimals can cause an error. If you come across the specifications for a SLGR let me know the UTM precision, I'm leaving for a road trip in a few hours and a bit busy.

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4 hours ago, 31BMSG said:

I never implied that it be used in a caching application or it was a consumer item. I was merely pointing out the method I was taught in 1991 that I still use today, and that comparing a screen with 4 decimals to a page with 3 decimals can cause an error. If you come across the specifications for a SLGR let me know the UTM precision, I'm leaving for a road trip in a few hours and a bit busy.

 

I can't find any specs for UTM for the SLGR or PLGR, but the Wikipedia article for the much newer DAGR shows UTM in only whole metres. I doubt that a non-precision unit from 14 years earlier was using 12 more decimal places. It just occurred to me that maybe you meant 12 digits, not 12 decimal places?

220px-Defense_Advanced_GPS_Receiver.jpg

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On 8/20/2019 at 2:52 PM, The A-Team said:

 

I can't find any specs for UTM for the SLGR or PLGR, but the Wikipedia article for the much newer DAGR shows UTM in only whole metres. I doubt that a non-precision unit from 14 years earlier was using 12 more decimal places. It just occurred to me that maybe you meant 12 digits, not 12 decimal places?

220px-Defense_Advanced_GPS_Receiver.jpg

Apologies, been in the mountains but thanks for the research.

 

Who knows, it's been almost 30 years but I know we were required to report the location of an item hourly in UTM not MGRS . No matter, for the moment Geocaching is about minutes to three decimals. I understand we're not landing something on Mars but when the number of digits displayed on the GPSr don't match what GS lists without adding, subtracting, or ignoring I get the impression "good enough" is in action. Maybe Galileo will display minutes to four decimals but until GS lists four decimal caches, .123 is not the same number as .1234.

 

As a consumer looking at coordinates GS has published and comparing those to navigational devices I've purchased for more than $30 a year do I still have to decide whether to round-up, round-down, or shake it all about? It's not about precision or accuracy, it's about numbers matching, something you can glance at and say "yep, same number".

 

 

 

 

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I have a question that relates to this discussion. When I submit a waymark, I use three digits after the decimal point (like on the geocache page). But once I submit the waymark, from then on, if I edit the page there are always four digits after the decimal point. It's permanent. The waymark page only shows 3, unless I'm on the edit page, then there's four. Why?

Don't laugh, but I wonder how does the system know what to add as the fourth digit, and why only on the edit page? I've always wondered about this.

 

Thanks for helping me understand.

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Computers use decimal degrees to perform their calculations and GPSr's are computers.  Humans prefer degree/minute formats.  If you enter coordinates using DD MM.MMM they will be converted internally to DD.DDDDDD.  Take a look at a typical GPX file and you will see the coordinates are in decimal degrees, up to six decimal places, e.g. <wpt lat="42.155317" lon="-72.328767">.   So in this case, if you entered 42° 09.319’ your computer will convert it: 42° + (09.319’ / 60’) = 42.155317.  After the computer determines a solution it will convert its answer back into degree/minutes: 42° + (60 * 155317) = 42° 9.319020 for display purposes.  The number of decimal points displayed to the user indicates the precision of the GPSr’s solution, not its accuracy.  Which is better to display to the user, 9.319 or 9.3190?  With the number 9.319 being displayed the fourth decimal place could be less than 5 or greater than 5.  You are assuming (or you're guessing) it is less than 5, but you don’t know for sure.  When it displays  9.3190 you know for sure that 9.319 is definitive and correct.

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8 hours ago, Capt. Bob said:

Computers use decimal degrees to perform their calculations and GPSr's are computers.

 

Actually computers use binary to perform their calculations. While not knowing the intricacies of the algorithms used to compute location from the satellite signals, there's a good chance they're all done internally in radians since they're the natural units for all the trigonometric functions, with conversion to degrees done as the last step for display purposes.

 

8 hours ago, Capt. Bob said:

Which is better to display to the user, 9.319 or 9.3190?  With the number 9.319 being displayed the fourth decimal place could be less than 5 or greater than 5.  You are assuming (or you're guessing) it is less than 5, but you don’t know for sure.  When it displays  9.3190 you know for sure that 9.319 is definitive and correct.

 

When it displayed to 3 decimal places, it rounded to nearest (I've verified that as I have screenshots I took of a waypoint before and after the change), so it would be somewhere between 9.3185 and 9.3195. In other words, it was doing automatically what you now need to do in your head.

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