[Qgis-developer] QgsGeometry, Geos and SFCGAL

[Nyall Dawson]

On 12 March 2017 at 19:23, G. Allegri <giohappy at gmail.com> wrote:
> Thanks Sebastiaan for raising this point. It's clear that if (SF)CGAL was
> somehow introduced inside the core it would need maintanance.
>
> Nyall, I agree with you. CGAL shouldn't overlap GEOS, even if its robustness
> (infinite precision) can make the difference.
> The real benefits would arise if/when QGIS will want to widen its SQL/MM
> geometries. TINs, polyhedral surfaces, or simply 3D predicates considering
> the z coordinate in 2.5D geoms.

Good point.

Something I forgot to add in my original reply - instead of investing
time into utilising CGAL instead of GEOS, I'd rather see us
investigate swapping out GEOS calls to Boost::geometry calls. The
boost geometry algorithms are really nicely implemented, and their
interface avoids the need to convert between different object types
(ie QgsGeometry->GEOS). This could potentially be a big
performance/memory usage win.

Nyall