which data structure is appropriate to query “all points within distance d from point p”

Question

I have a 3D pointcloud and I\'d like to efficiently query all points within distance d from an arbitrary point p (which is not necessarily part of the stored pointcloud)

Answer 1

Well, it depends on what other uses you need for the data structure.

You can have a list of distances from point p to other points, ordered by distance, and map these lists to the points with a hashmap.

map:
p1 -> [{p2, d12}, {p4, d14}, {p3, d13}]
p2 -> ...
...

You can look up the point in the map, and iterate the list until the distance is higher than required.