[Qgis-developer] What is the roadmap to completely manage 3d geometries?

[Luigi Pirelli]

Hi,

since 2.10 there is supprt to curves and Z/M... but some methods still
remain managing geometries in 2d way implicitly, eventually causing
incorrect calculations.

the realised the problem reading a Nyall commit
https://github.com/qgis/QGIS/commit/4c704be60636b8f9994cb7aabb7d9da64c5093ab
There you can read comments.

in this commit (and probably in a lot other places) all vertex
distances are calculated as proyected in 2d, obviously creating error
if Z is present => routing algs could be affected.

as Nyall suggests, there are some questions related to this commit...
but IMHO wider questions related with the complete V2 geometry
support.

"""
Could we move this discussion to the dev list for wider exposure? I
don't work with 3d geometries often enough to have a strong opinion
about what the correct behaviour is. I figure there's 4 options:

always do 2d calculations
always use 3d calculations if z present
rename these methods to distanceToVertex2d and add seperate 3d methods
(clutters API)
add an extra bool parameter for ignoring/considering z values (more
confusing API)
"""

let us know your opinion

regards

Luigi Pirelli

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