Hi David, Yes, yes. I've tried the same! We can say that a spatial join can beat an attribute based join in performance!
Regards, Jorge Às 23:51 de 14/03/21, David Strip escreveu: > On 3/14/2021 5:34 PM, Jorge Gustavo Rocha wrote: >> Hi David, >> >> Thanks for replication this issue. "Join attributes by location >> (summary)" is definitely the best choice for this use case. It creates >> the new layer in a few seconds. That's why I think we are missing >> something (spatial indexes?, dependency graph?) in the expression engine. >> >> There are anomalies in the data. That's almost the same with any dataset >> we start working with :-) >> >> Regards, >> >> Jorge > I tried a different approach, using aggregate, matching on the country > name, thinking that would be faster than a spatial check. > I created a new field with the expression: > > aggregate( '03-03-2021','sum', "Confirmed", "Country_Region" ILIKE > attribute(@parent,'SOVEREIGNT')) > > Much to my surprise, this was slower than "Join attributes by location > (summary)" > J. Gustavo -- Jorge Gustavo Rocha Departamento de Informática Universidade do Minho 4710-057 Braga Gabinete 3.29 (Piso 3) Tel: +351 253604480 Fax: +351 253604471 Móvel: +351 910333888 skype: nabocudnosor _______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
