Hi,

Does anybody know the current documentation of the precision of the globe coordinate datatype? This precision was introduced after the original datamodel discussions.

I used to believe that it was a rough, informal indication of a precision based on an (easy-to-process but necessarily rather inaccurate) bounding box. After all, the UI only allows for a small number of predefined settings.

However, the data contains many values with precision value "null". What is this supposed to mean and how should consumers treat it? The precision of a measure cannot be "0" (and in any case, 0 is none of the supported constants in the UI).

In addition, the data also contains some seemingly arbitrary numbers as precision, such as a precision of 10.372851422071 degrees for the location of Oceania (Q538). Now given the fact that the Earth is not flat and Oceania is not a square, I fail to see the possible utility of such an extremely detailed custom precision value. My point is that the area (bounding box) that any such tolerance describes on Earth depends on the location of the center point, and is hardly capturing our exact amount of uncertainty in any strong sense. So why bother with such custom values?

At first I thought this would be an error in the data, but the UI has a special handling for it (quite literally: it shows the word "special" with the precision in parentheses). However, I cannot edit this value as a user without resetting it to one of the predefined values. This seems a huge limitation, which would require a very good reason for supporting such odd values at all. Or is the behaviour of the UI just a way of recovering from an error while avoiding to simply fix it by itself? Should we have a bot that corrects such cases to the nearest existing precision setting?

Cheers,

Markus

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