[Qgis-user] QGIS Analytical combinations

[enricofer]

I suggest you to put everything in spatialite database and, assuming that
1) GRID is the polygon layer with grid definition
2) POINTS is the point layer with population data
3) POINTS has a field "pop" with population data
4) both layers have a keyfield named "id"
5) both layer have "geom" as geometries field

Run the following query with dbmanager:

SELECT DISTINCT GRID.id, SUM(POINTS.pop) AS POPxGRID
FROM POINTS
INNER JOIN GRID ON ST_Within(POINTS.Geometry,GRID.geom)
GROUP BY GRID.ID

you will get a table with a reference to a grid feature ID and the sum of
the population of the points that are within the grid feature

I hope this help you.

Enrico Ferreguti



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