[Digikam-devel] [digikam] [Bug 326406] A picture without geolocalisation is localized in North Pole

[Nicofo]

https://bugs.kde.org/show_bug.cgi?id=326406

--- Comment #11 from Nicofo <nicofo at tuxfamily.org> ---
Hi Gilles, 
I have checked other pictures and indeed DOP is confusing:

(In reply to Nicofo from comment #8)
> - GPS Data Degree of Precision do not exist (when GPS not activated -> as a result the localization is Equator)
> - GPS Data Degree of Precision = 0 (when GPS activated, but localisation not performed -> as a result localisation is North Pole)
This is correct, but I have to add that for the pictures that are well
localized, GPS Data Degree of Precision can 0 as well !! (I have pictures with
values from 0 to 25, ...)

So I would NOT use the DOP parameter (moreover, as you mentioned with iphone,
this parameter is not managed by every device).

There are 2 cases that must be detected and discarded because the picture
doesn't contain GPS information:
1) GPS is not activated (or the camera does not contain a GPS): in that case a
lot of GPS tags are not present. In the case of my camera (panasonic tz40),
there is no "GPS Latitude", "GPS Longitude" tags.
Note however that there could be some GPS tags even when GPS is not activated:
like "GPS altitude" (=0), "GPS Version ID", "GPS Image Direction" (I guess if
there is a compass, working even if GPS not active).
2) GPS is activated but localisation not done. In my case, all the GPS tags are
present, but some tags are NULL:
- DOP (but we know now that this tag cannot be used)
- GPS Date Stamp
- GPS Time Stamp
- GPS Area information
[See comment #6 for pictures examples]

To summarize, I would consider GPS info is not valid if one of the following
condition is met:
- tag "GPS Latitude" or "GPS Longitude" is not present
- tag "GPS Date Stamp" = 0000:00:00
(to check with other devices, but this seems to be generic).

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