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

[Greg Troxel]

Vedran Stojnović via QGIS-User <qgis-user at lists.osgeo.org> writes:

> QGIS should do on-the-fly reprojection, but you can count on only the
> defined vertices of geometry as far as I know.

Do you mean:

  The meaning of a linestring is the points at vertices, and between
  them, a straight line in whatever CRS the data is currently expressed
  in?

and that the points are transformed, and then the straight line between
is straight in the sense of the target CRS?

I think that's what Javier is trying to do: to take a line with two points in
EPSG:3395, and a line *that is straight in 3395* with three points, and
transform it all to 3857.

That should result in a line (layer 2d) that is straight in 3857, and
then two lines, each straight in 3857, that are from lower-left to
middle and middle to upper-right, with each transformed. 

> You can execute "Densify by interval" or "Densify by count" on source
> geometries in source CRS - you can use the "Edit features in place" option.
> This will convert your "line" to "linestring" with many smaller segments.
> Please check if this solves your problem?
>
> I remember that there was an announcement for some QGIS 3.x version that
> this "densification" of vertices is done automatically, but maybe it
> stopped working or works for only certain source CRSs (maybe the ones
> defined in Lat-Long) - it seems that it works for "Identify tool".

Are you suggesting that when qgis transforms a linestring, it is doing
some kind of densification to show a line in the target CRS which is the
transform of e.g. the source-CRS line that fits in the canvas?