Delaunay Triangulation inconsistency

[KonstiDE]

What is the bug or the crash?

When applying the native delaunay trinangulation process only the centroids of hexagons, we would expect a fishernet kind of layer. However, the triangulation feature fails after almost producing the right output...

Steps to reproduce the issue

Create a hexagonial grid with the extend: 8.596003700,9.835141800,41.386694700,43.050699100 [EPSG:4326]
Use Vector > Geometry Tools > Centroids on the grid
Apply Delaunay Triangulation onto the centroids

Versions

QGIS version: 3.22

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[agiudiceandrea]

@KonstiDE could you please provide all the needed relevant parameters of the "Create grid" algorithm in order to create the grid with which the issue does occur?

[KonstiDE]

For width and height, I use 10.0 kilometers for Hspacing/Vspacing and 0.0 for the Hoverlay/Voverlay. CRS is the project default: EPSG:3857 - WGS 84 Pseudo-Mercator

[KonstiDE]

Any updates?

[agiudiceandrea]

@KonstiDE, I can only confirm that the issue occurs using the latest QGIS 3.28 and QGIS 3.30 on Windows.
It seems the GRASS v.delaunay algorithm does a better (almost perfect) job in such situation.
The "Voronoi polygons" algorithm (qgis:voronoipolygons) is also affected by the same issue.

[KonstiDE]

Any updates?
Still fails in QGIS 3.32.3 (Lima)

[alexbruy]

It is still open. Obviously no.

[agiudiceandrea]

@KonstiDE, it seems to me the issue no longer occurs on Windows using the latest QGIS 3.35.0-Master nightly build and the upcoming QGIS 3.34.0. It may have been fixed by #53787. Could you please check ASAP?

[KonstiDE]

Works like a charm, thank you