[Qgis-user] Unexpected comparison Web-Mercator vs Mercator

[Kai Borgolte]

Am 23.07.2025 um 15:42 schrieb Vedran Stojnović via QGIS-User:

> I remember that there was an announcement for some QGIS 3.x version that 
> this "densification" of vertices is done automatically,

So I suspect we are seeing this "at work" here, causing unexpected 
results. Can someone find this announcement or any docs?

Javier's 2p is in EPSG:3395 with a two point linestring:
LineString (0 0, 8000000 10000000)

If I create a new layer in EPSG:3857 and draw a line using the same two 
points (snapping), I get
LineString (0 0, 7999999.99999999906867743 10039255.88279054872691631)

Whatever map projection is set, I would expect both two draw as a 
straight line between the endpoints. But QGIS does show them about 4 km 
apart in the middle, so at least one of them is not a straight line.
-- 
Kai Borgolte, Bonn