overlapping-featuresqgis
I've been through the similar questions and can't see a suitable answer.
I have a shapefile with 1000's of polygons that cover the country. What I want to do it create a regular spaced grid of points across the country (every 10x10km for example). Then for each point count how of the polygons in the other shapefile overlap that point. Essentially the output point dataset will indicate hot and low spots across the country.
I'm using QGIS 3.20. I need to understand the high and low extents.
You might want to create centroids for your grid of polygons, then and attach the weight value of the data with no exact location (located in a grid cell) to the centroids. This can be accomplished by:
That should give you the weights (from each polygon in the grid) into a point layer of centroids. Now you can merge these points together with your actual point locations to create one point vector with weights, and do any further heat maps etc.
If you want to total the weight per polygon, that's an additional process. I do these kinds of things in a database. Import both the polygon grid and the points into Spatialite, for example then try these SQL commands in Spatialite-gui:
ALTER TABLE grid ADD COLUMN total_weights REAL;
UPDATE grid SET total_weights=(SELECT SUM(p.weight) FROM points AS p WHERE ST_Contains(grid.geometry, p.geometry));
(Of course, you'll have to adjust the column names and table names)
I would recommend using the Count Overlapping Features (Analysis) tool.
Generates planarized overlapping features from the input features. The count of overlapping features is written to the output features.
Best Answer
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