tool for point aggregation and mean calculation

Question

I have the huge number of points spread across some map.

Is it possible to calculate the mean value of a parameter in the points of a small area and make one point for the same so that the total number of points in the map can be reduced?

Answer 1

One tool available in QGIS processing toolbox is SAGA Points thinning tool (in Processing toolbox | SAGA | Vector point tools).

When activated, you will find two input parameters to set:

• Attribute: The attribute field you want to calculate mean.
• Resolution: The diameter (m) of a search circle in which a representative point is chosen or newly created. Increase this value if you need to severely reduce the points.

It returns a Thinned Points layer, and its attribute table has the mean (among other parameters = count, mean, min, max, sd) of the value you chose for Attribute parameter.

Answer 2

I think that there isn't exist an unique tool to do it. I propose you the following process from an example like this:

1. CONVEX HULL around you points using a grouping attribute.
2. POLYGON CENTROIDS to get the central point of those new polygons. This could work as you aggregation point. It should seems something like this:
3. Calculate statistics by categories from your point data.
4. You will get the following statistics.
5. Last step is to make a join of the centroid with those grouped statistics.

Hope it helps.