[QGIS-Developer] timzonefinder vs point in polygon

[C Hamilton]

I tested "Join attributes by location" and it is faster although I must
have a slower machine to run on than yours.

Most of the time the use case is single point matching against the time
zone polygon. You mention that "Join attributes by location" is best used
when the number of points >> number of polygons. What is the best method to
match a single point and do that many times for uses such as during mouse
motion to report the time zone of the cursor to the status bar.

Calvin

On Fri, Feb 5, 2021 at 6:30 PM Nyall Dawson <nyall.dawson at gmail.com> wrote:

> On Sat, 6 Feb 2021 at 07:54, Andrea Giudiceandrea <andreaerdna at libero.it>
> wrote:
> >
> > C Hamilton wrote
> > > Using the algorithm Vector->Geoprocessing Tools->Intersection: 4
> minutes,
> > > 4
> > > seconds
> >
> > Hi Calvin,
> > maybe it could be better to use the "Join attributes by location"
> algorithm.
> > It only takes few seconds to preform the join.
>
> Confirmed - for me it only takes ~2 seconds, and that's on an
> non-optimised debug build! There may be a few % more performance boost
> on the proper QGIS release builds.
>
> "Join attributes by location" has a bunch of extra logic to optimise
> the method that the join is performed, which really pays off in this
> particular situation (matching points to polygons, where number of
> points >> number of polygons).
>
> Nyall
>
>
>
> >
> > Regards.
> >
> > Andrea
> >
> >
> >
> > --
> > Sent from:
> http://osgeo-org.1560.x6.nabble.com/QGIS-Developer-f4099106.html
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