Fixed-radius near neighbors

Fixed-radius near neighbors is a way of finding things that are close together. Imagine going to a park and you want to find all of the trees that are in a certain radius from where you are standing. You can use fixed-radius near neighbors to help you find those trees. It looks for anything that is within a certain distance (or radius) from where you are. That way it can tell you which trees are close to you and which ones are far away.