Geo-location questi...
 
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Geo-location question

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(@tootypeg)
Posts: 173
Estimable Member
Topic starter
 

Hi,

First, geo-location is something I am not an expert on, and I am probably a little guilty here of not in-depth researching before posting but my quick scan didn't provide the answer, but this stems from a debate I was having recently about the accuracy of geo-location data. This led to the following questions-

1. If 10 people stood in the same spot with the same make/model of phone at same time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

2. If 10 people stood in the same spot with different make/models of phone at same time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

3. If 10 people stood in the same spot with different / same make/models of phone at a different time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

….so I guess what I am asking is, is geo-info accuracy dependant on "handset" or gps saterlitte system, at which point meaning that it doesnt matter what device you have?

….also, obviously, I could test this, but im after a "quick" set of thoughts D 😯

 
Posted : 17/06/2017 5:43 pm
jaclaz
(@jaclaz)
Posts: 5133
Illustrious Member
 

I don't know.

I guess you will need to state some unit of measures for the accuracy/inaccuracy.
And possibly different photo apps may use different approximation.

There are IMHO three different levels of abstraction
1) the capability of the hardware (and the technology used)
2) the capability of the OS to gather the info
3) the capability of the photo app/program to write correct info from the above

Anyway, an image is worth a thousand words

Full article
http//www.blog.jimdoty.com/?p=14661

If we are given a few meters of approximation, the answer to the final question is "Anything will do".

BUT, it's not as simple as it seems (older experiment)
https://blogs.esri.com/esri/gisedcom/2011/04/15/gps-vs-smartphone-part-1-of-2/
https://blogs.esri.com/esri/gisedcom/2011/04/22/comparing-the-precision-and-accuracy-of-locations-recorded-by-gps-vs-smartphone-part-2-of-2/
assisted GPS
https://en.wikipedia.org/wiki/Assisted_GPS
may well change the results greatly.

jaclaz

 
Posted : 17/06/2017 7:15 pm
(@c-r-s)
Posts: 170
Estimable Member
 

A quick set of thoughts (only) on GPS/Galileo/GLONASS

1. If 10 people stood in the same spot with the same make/model of phone at same time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

Yes, roughly. Only few manufacturing errors affect a "level of accuracy".

2. If 10 people stood in the same spot with different make/models of phone at same time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

No. How satellite navigation is integrated into the hardware, has got significant influence on its accuracy.

3. If 10 people stood in the same spot with different / same make/models of phone at a different time and took a photo enabling geotagging, would they all provide the same level of accuracy/inaccuracy?

No, since accuracy of satellite navigation receivers drifts with temperature, which typically varies with time of day.

 
Posted : 17/06/2017 10:34 pm
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