[Qgis-user] Pseudo Mercator(OSM) @ EPSG:4326 bug?

[Idan Miara]

Thanks for your reply,
How can I check if QGIS is applying the transformation or if it asks the
service to provide the tiles in 4326?

On 5 Mar 2018 11:17, <b.j.kobben at utwente.nl> wrote:

> Most likely the service you are using is only able to provide its maptiles
> in 3857 and does not respond to the QGIS request to provide them in 4326
> (or responds, but incorrectly)...
>
>
>
>
>
> --
>
> Barend Köbben
>
>
>
> On 05/03/2018, 09:39, "Qgis-user on behalf of Idan Miara" <
> qgis-user-bounces at lists.osgeo.org on behalf of idan at miara.com> wrote:
>
>
>
> Hi,
>
>
>
> I might have found a bug related to transformation of layer CRS from EPSG:3857
> (Pseudo Mercator) to EPSG:4325 (WGS84 Geo).
>
> I'm attaching a few images to demonstrate the issue.
>
>
>
> Steps to reproduce:
>
> I've load OSM in QGIS 2.18.16 (or 3.0,same results)
>
> via Tile Server (XYZ):
>
> https://a.tile.openstreetmap.org/{z}/{x}/{y}.png
>
>
>
> Then set the CRS to EPSG:4326 (WGS84 Geo)
>
>
>
> I've also loaded a global bounds vector layer (EPSG:4326)
>
>
>
> In scale 1:100,000,000 it seems that the Pseudo Mercator transformation to
> 4326 is flawed, as the OSM and the vectors are not aligned.
>
> In scale 1:50,000,000 it seems OK when the extent is the middle of the
> map, but if I pan to the south/north it seems distorted again.
>
>
>
> If I set the project CRS to EPSG:3857 (Pseudo Mercator) as the CRS of the
> OSM tiles, so the vector layer would be transformed instead, then they do
> align in all scales (picture with the blue vector layer).
>
>
>
> It doesn't look like a problem of precision of the transformation from
> 3857 to 4325 because it's way off.
>
> Is that a bug or am I missing something here?
>
>
>
> Kind regards,
>
> Idan.
>
>
>
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