Buffer with unknown distance by adding numerical values of a column until a maximum

Question

In my QGIS project, I have a vector of polygons representing slope zones around an archaeological site and I want to calculate the area which is necessary to supply the ancient population with a specific resource.

The slope vector incorporates the potential yield of this resource per feature. I have the total number of yield and I want to sum up the values of every feature from a point in the center of the site until it reaches that maximum.

Now I am looking for a possible way to create this extraction zone and I think in using a buffer. I noticed that there are only tutorials for buffers with fixed distances, but I couldn't find a solution with that.

In my opinion the best thing would be an expression consisting of the buffer and a condition instead of the distance. Unfortunately, I haven't much experience yet and have no idea how to do this.

Answer 1

In QGIS 3, there is an algorithm that creates a multi-ring buffer. Go to Processing > Processing Toolbox

You get:

You can use an expression to calculate the number of rings and the distance between every ring