Re: [QGIS-Developer] Intersections with Qgis

Johannes Wildermuth Mon, 06 Apr 2020 23:36:26 -0700

Hi
Thank you all for your quick answers.
Regards
Johannes

Gesendet: Montag, 06. April 2020 um 12:51 Uhr
Von: "Bo Victor Thomsen" <[email protected]>
An: [email protected]
Betreff: Re: [QGIS-Developer] Intersections with Qgis

Johannes -

The actual intersection code can contain a pre-check of bounding box intersection. This will probably decrease computation time significantly for the check:

for i, geom_i in enumerate(geoms):
for j, geom_j in enumerate(geoms):
if j > i:

# Check bounding box first... result = geom_i.boundingBoxIntersects(geom_j) if result: # Bounding box intersects, check actual geometry... result =geom_i.intersects(geom_j) # Do something with result...

--
Med venlig hilsen / Kind regards

Bo Victor Thomsen

Den 06-04-2020 kl. 11:36 skrev Johannes Wildermuth:

Hello developers
I've been currently working on a python plugin in which I have to find all possible intersections on one layer. I want to improve the efficiency of this task. It roughly looks like this:
for i, geom in enumerate(geoms):
for j, geom in enumerate(geoms):
if j > i:
//intersections
Is there a faster way? Perhaps with multithreading / rtree?
Regards
Johannes Wildermuth
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Re: [QGIS-Developer] Intersections with Qgis

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