Decimals of Lat/Lon and UTM coordinates

Sonny shared this question 18 months ago
Answered

I think since the latest update of Locus, several coordinate systems have got an (for almost all users) unnecessary number of decimals.

WGS (x.x°): 6 decimals (= ca. 0.1 m)

WGS (x° x.x'): 4 decimals (=ca. 0.1 m)

WGS (x°x' x.x"): 3 decimals (= ca. 0.01 m)

UTM: 3 decimals (= millimeter)

Hardly anybody needs that precise coordiantes. Hardly any consumer GPS-receiver nor Air images are able to deliver that precise coordinates.


For example in the Geocaching-World N12° 34.567 (= 3 decimals) is standard, which is almost precise to 1m. Any more precision will lead to more errors and more unnessecary work for input of coordinates. And also many Geocachers don't even know what to do with 4-decimal formated coordinates.


Please change back the default precision of the individual coordinate systems to about 1-2 m. Any more precision should be optional enabable within the settings, although I doubt that many Locus users will really need that sub-meter precision of coordinates.

Replies (7)

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I have the same problem, please bring back the format with 3 decimals (xx° xx.xxx).

Ano, mám ten samý problém. 4 desetinná místa jsou moc, prosím vraťte klasický WGS formát (xx° xx.xxx)

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Hello sonny,

WGS (x°x' x.x") as well as UTM display one less decimal. In all cases, accuracy of coordinates should bring sub-meter accuracy. More and more devices are coming close to one meter and in some cases even a little better.

If I revert this option back, I'm sure that within two years, I'll have to change it again ... accuracy can't be stopped :).

Menion

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Hi Menion, I doubt that most of locus people will


a) really need sub-meter accuracy (what is the use-case for this outside of professional land survey?)

b) consumer-devices may DISPLAY even micrometer-coordinates but that has nothing to do with the real measured accurancy. Non-professional devices (which are almost all devices Locus are running on) will never measure with real sub meter accuracy compared to fixed surveyed coordinate refference points. They will fluctuate at least within a meter around this. Don't mix it with the feature of (modern) devices to display large amount of unnessecary, unreal decimals...

I don't want to read all the time 4 decimals or a trailing "0" like N48° 12.3450 during Gecoaching. They are more confusing, prone to input errors - especilly for non-technical Geocaches than the usual 3-decimal format.

At least please make the the number of decimals adjustable within settings. If some useres really need sub-meter accuracy (I'm still curiuos what's the user case outside of professional survey for that) they are able to activate displaying more decimals.

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Interesting.

Hi sonny, I do not use sub meter GPS equipment. Land surveyors use this and they provide the (BE) coordinates in the Lambert system. For example, I now have a dispute about a border separation, measured by 2 professional surveyors, one of whom might have had drunk a beer too much during his measurement. If you do not have the necessary equipment yourself, it is difficult to determine what and where exactly the measurement error occurs. Since I had the coordinates of both surveyors, even with the unprofessional Locus map, and using solid WMS map data, I could clearly see which of the two was possibly "bottled up". So I can really appreciate that precision in Locus.


Do not have a problem with your proposal to limit this via config.cg.


Moreover, more precision is also affordable for amateurs who want it. Google u-blox and RTK. Indicating the exact match in a matchbox at the 'treasure hunting' that is not yet possible, but the search for the matchbox itself may already be clearly more precise even for amateurs with better than 1 meter location precision.

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I would very much prefer 3 decimals, too. No 4th digit needed (now).


There's also a drawback in usage when switching to a 4th digit:

when opening any point (geocache or not) it's not possible to see the full coordinates anymore (neither in portrait nor in landscape mode);


now it takes 2 additional actions since you have to enter coordinates edit mode

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Hi guys,

oki, I'm convinced ... for now :). In the next 3.48 version, coordinate precision will be reduced to meter accuracy.

In future, I'm sure that additional precision even in Locus Map will be needed, anyway, it will be in a time when a) most of the device will be able to have sub-meter accuracy (for example over RTK or L1/L2 frequencies) or b) I'll add this as an optional parameter.

Thanks for the feedback.

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b) I'll add this as an optional parameter.

+1 from me

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I agree it should be "b) I'll add this as an optional parameter." for people who want sub-metre accuracy.

Locus Maps needs to progress forwards and sub-metre accuracy will become commonplace in many devices in the future, some may already be using systems such as the Juniper Systems Geode and similar with Locus Map.

I use decimal degrees and would gladly support accuracy being taken a step further and allow the user to select up to 8 decimal places if they so wish and to be displayed as so throughout the app (currently truncated to 5 at the moment).

I for one can't wait to have sub-metre accuracy on a device such as a phone as I also use Locus Map to store points where I have located endangered insects (which could be a single plant in a dense area) so I can return to monitor them.

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Just for interest:

with 5 decimals you can define coordinates with a deviation from 0 to +/- 0.5 m to the theortical perfect measured coordinate. So the average deviation of a coordinate is 0.25 m with 5 decimals.

Why do people need a precision of 6 decimals (precision of some centimeters) or as you said even 8 decimals (precision of some 0.1 millimeters)...


And beside of this theoretical values and the user cases for coordinates <0.25 m: I doubt that there are affordable devices even in the future running Locus which are able to measure coordinates with deci-/centimeter precision. (Meaning this cm-coordinates measured by consumer devices are the same as measured with multi-thousand $ professional receivers)

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