Extract the maximum weight from each subset of overlapping points

Hi everyone,

I have a set of coordinates with some overlapping points (lat, lon).

Here's an easy example:

lat   =  [ 0 0 0 1 2 2 2 ] ;
lon   =  [ 0 1 0 4 5 6 5 ] ;
weight = [ 1 2 3 4 5 6 7 ] ;

Coord = [0 0; 2 5] ;
MaxWeight = [3, 7] ;

so evidently the first and the third points, as well as the fifth and the seventh, have the same coordinates Coord(1,:) and Coord(2,:).

I would like to write a code so that I can determining the MaxWeight vector by finding all the subsets with overlapping points and extract the maximum weight from each subset.

Thanks in advance

Answer 1

[Nolan Canegallo]

Probably not the most efficient way, but this seems to solve your problem.

clear; clc;
lat   =  [ 0 0 0 1 2 2 2 ] ;
lon   =  [ 0 1 0 4 5 6 5 ] ;
weight = [ 1 2 3 4 5 6 7 ] ;

overlap = any(and(lat(:)==lat, lon(:)==lon)-eye(length(weight)));
Coord = unique([lat(overlap);lon(overlap)]','first','rows');
for i = size(Coord,1):-1:1
    MaxWeight(i) = max(weight(lat==Coord(i,1)&lon==Coord(i,2)));
end

Results:

Coord =

     0     0
     2     5


MaxWeight =

     3     7