I have a layer of point locations distributed country-wide. I would like to create a new point layer that shows the mean or center of mass of the points, but grouped based on the value of a field, such as province or municipality. Thus we have the mean coordinates of the points within each province or municipality.
How do I do this in QGIS?
One can try the "Mean coordinate(s)" geoalgorithm.
Computes a point layer with the center of mass of geometries in an input layer.
An attribute can be specified as containing weights to be applied to each feature when computing the center of mass.
If an attribute is selected in the parameter, features will be grouped according to values in this field. Instead of a single point with the center of mass of the whole layer, the output layer will contain a center of mass for the features in each category.
Let's assume there is a point layer called 'points_test' with its attribute table, see image below
"id" : a unique identifier
"Group" : a grouping field for points (corresponds to your province or municipality). In case you do not have these values, please use additionally the "Join attributes by location"
"Weight" : a field with weights
It will return just one dot (a yellow one).
'Unique ID field'It will result in one point for each unique group, check the red dots
'Unique ID field' and the 'Weight field'It will result in one point for each unique group based on the points' field with weights, see the green dots
One should always distinguish between:
Only in specific (and rare) cases, they are equal.
References: