[Qgis-developer] Wrong reprojection if using different datums?

[Agustin Lobo]

Thanks,
In that case, before the problem is fixed,
it should be prominently stated that conversion
of coordinates involving different datums in QGIS is wrong.
Otherwise, this implies a serious loss of reliability. This
is an important matter for people using GPS coordinates, which
are often in WGS84 by default. Users cannot rely on "on the fly"
reprojection, but should set their GPS on the same CRS as
the maps they will be using later.

Agus


Paolo Cavallini wrote:
> Agustin Lobo ha scritto:
>> different in both datums? I suspect that proj4 (behind QGIS)
>> is not using the +towgs= field.
>>
>> Any opinions on this problem?
> 
> Hi Agus.
> I think QGIS is mostly ignoring +twgs parameters. This is the root of
> several bugs, and I think is one of the major issues to be solved.
> Mentioned also in our bug squashing initiative:
> http://www.qgis.org/wiki/Bugs#Projections
> Unfortunately, it did not attract much specific funding jet.
> All the best.