[QGIS-Developer] Is the measurement tool using proj library?

[Andreas Neumann]

Hi,

Am 19.07.19 um 23:47 schrieb Nyall Dawson:
> On Fri, 19 Jul 2019 at 23:15, Andreas Neumann <a.neumann at carto.net> wrote:
>> Hi Nyall and others,
>>
>> I was wrong, there is no difference in behaviour between proj493 and proj520. Nor is there a difference between Linux and Windows.
>>
>> We, as a user, made the mistake of creating test data in a new empty layer at around (0,0) and my colleague in a totally different area in the coordinate system in an area that isn't valid for the EPSG:2056 projection. The EPSG:2056 projection only works reasonably well in the bound of approx. 2485000 1075000 2828500 13000000
> Glad I'm not the only one who has made this mistake!!

;-) I felt so embarrassed that it took me quite long to find out about 
my/our mistake.

>
>> I wonder if it would make sense to issue a warning if a user creates data outside of the valid bounds of a projection? It would definitely make sense for stupid people like myself ...
> This sounds like a good idea to me. When would you propose that we
> raise the warning? Possibly on saving edits to a layer?

Yes - on saving a layer it it would make sense to check against the 
valid boundaries of a projection (if we have this information 
available). Probably not during editing. I think it should not prevent 
saving, if someone wants to that, but a warning in the messagebar would 
be useful to have, or perhaps even with a yes/no question - do you 
really want to save? Do you know what you are doing?

Thanks,

Andreas