[GIS] How to assign a grid of point data to corresponding grid of polygons

Question

I'm using QGIS 2/12.3

I have a point layer with modelled data on a 1km grid, each point has a value (0-5, modelling temperatures) and lies at the centre point of a 1km grid square.

I also have a polygon layer which is of 1km squares.

I need to assign the points values to the corresponding polygons.

If I use intersect, the output layer is points, not polygons.

(I need to do this so I can intersect the km squares with another layer to find the average value for each polygon).

I realise one way might be to add a new column to the attribute table and paste data across – but I need some guidance.

Answer 1

This is just a visual explanation of Join attributes by location.

(1) Let's assume you have a point layer (Point_temperature) with id and mod_temp fields.

(2) You also have a polygon layer (Grid) which has its own id field. (Note this id is unrelated with another id in the point layer.)

(3) Go to Vector | Data management | Join attributes by location.

(4) Make sure the Target is your Grid layer, and select Take attributes of the first located feature option.

(5) It will return a Joined layer (new polygon layer) in which you will see id_1 and mod_temp copied from the point layer.