Thanks everyone. I went ahead and updated the geodesic transformations tool in Shape Tools to use the QgsProcessingFeatureBasedAlgorithm algorithm. I didn't know that existed and I had only used QgsProcessingAlgorithm, I also updated the geodesic transformations tool to use data derived overrides. I had a hard time finding documentation and python examples on how to do it, but I believe I have it all working now.
On Wed, Aug 25, 2021 at 2:47 AM Etienne Trimaille < etienne.trimai...@gmail.com> wrote: > Indeed, if you can, you should use a QgsProcessingFeatureBasedAlgorithm > algorithm. It will make some shortcuts for you and the code is shorter > because you will only have a single feature to process. > > Have a look to existing source code : > https://github.com/qgis/QGIS/search?q=QgsProcessingFeatureBasedAlgorithm > > Le mar. 24 août 2021 à 04:55, Ujaval Gandhi <uja...@spatialthoughts.com> > a écrit : > >> If your algorithm works on each feature independently, processFeature() >> is preferred. If you need to work with layers, you need to use >> processAlgorithm(). I demonstrate this with an example at >> https://spatialthoughts.com/2019/04/05/geodesic-buffers-in-qgis/ >> >> On Mon, 23 Aug 2021 at 10:25 PM, C Hamilton <adenacult...@gmail.com> >> wrote: >> >>> I discovered that it looks like there is another way to deal with >>> processing algorithms. Rather than use processAlgorithm it looks like I can >>> use prepareAlgorithm & processFeature. I have always used processAlgorithm >>> and then iterated through the features. >>> >>> Is processFeature just as quick as using processAlgorithm (iterating >>> through the features)? Is one method preferred over the other? I think for >>> some algorithms using processFeature would make the code look cleaner. Are >>> there any gotchas in using the processFeature method? >>> >>> Thanks, >>> >>> Calvin >>> _______________________________________________ >>> Qgis-user mailing list >>> qgis-u...@lists.osgeo.org >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> >> -- >> [image: Logo] <https://spatialthoughts.com/> >> Ujaval Gandhi >> Spatial Thoughts >> mobile: +91-8095684687 >> email: uja...@spatialthoughts.com >> [image: LinkedIn icon] <https://www.linkedin.com/in/spatialthoughts/> >> [image: >> Twitter icon] <https://twitter.com/spatialthoughts> >> >> _______________________________________________ >> QGIS-Developer mailing list >> QGIS-Developer@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> >
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