[Qgis-user] Z and Elevation

[Manolo Terranova]

Thank you Greg.

EPSG 32632

attached data to this email,

Manolo

On Wed, Jun 28, 2023 at 11:48 PM Greg Troxel <gdt at lexort.com> wrote:

> Sebastian Gutwein via QGIS-User <qgis-user at lists.osgeo.org> writes:
>
> > Manolo,
> > You may already know this and be asking a deeper question that I am not
> > understanding but in case you are not:
> > The Z is the value derived from the geometry itself that QGIS uses to
> draw
> > the location of the point.
> > The Elevation is an attribute associated with the point (a field in the
> > attribute table).
> > There are many reasons that these might not be the same.
> > It could be that they were derived from two different sources or there
> was
> > a transformation that occurred that changed the Z value.
> > Hope this helps.
> > -Bas
>
> I am a beginner with dealing with height/elevation in qgis, but it seems
> obvious :-) that the Z value is interpreted with respect to the CRS,
> which must necessarily be a lat/lon/vertical.  Some 3D CRSes have
> vertical components that are HAE e.g. EPSG:7912, ITRF2014 lat/lon/hae,
> and some will have vertical components that are some kind of orthometric
> height, e.g. EPSG:5498, NAD83 lat/lon and NAVD88 height.
>
> So "Z should be ellipsoidal" is not in general true.
>
> (Plus, Sebastian's comments sound very useful, and you (Manolo) did not
> post your CRS and data schema.)
>
> Greg
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20230629/c8c7cc3a/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Dataset Manolo.zip
Type: application/x-zip-compressed
Size: 1573 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20230629/c8c7cc3a/attachment.bin>