How to return data points without the detected once while using Rangesearch function.

How to get red of the detected data points in the matrix [x y] (The points with in the range 0.5) and make the next code returns a new matrix [X Y] withOUT the detected ones with in the range 0.5 .

x = gallery('uniformdata',30,1,1);

y = gallery('uniformdata',30,1,10);

plot(x,y,'.')

k = boundary(x,y);

hold on;

plot(x(k),y(k));

%%get points at distance 0.5 from boundary 

idx = rangesearch([x y],[x(k) y(k)],0.5);

% plot the points

N = length(k) ;

for i = 1:N

plot(x(idx{i}),y(idx{i}),'O','color',rand(1,3)) ;

end

Thank you

Answer 1

[Walter Roberson]

points_within_range = unique([idx{:}]);
temp_matrix = [x, y];
output_matrix = temp_matrix(~points_within_range, :);

In my test, the resulting output matrix is empty, because with that distribution of points, every point is within 0.25 of some edge point. The average distance to some edge point was about 0.11

[Faez Alkadi]

Hello Walter,

I tried to change the distance from (0.5) all the way to (0.1). But I noticed the "points_within_range" is changing, though I still have an empty matrix for "output_matrix"

Thanks

[Walter Roberson]

Sorry, should be

output_matrix = temp_matrix(points_within_range, :);

[Faez Alkadi]

I think i didn't explain properly,

I'm looking for the rest of the points that are NOT within the range. The once that are almost in the middle of the shape. the first one should work, but i don't understand why it gives an empty matrix

Thank you so much.

[Walter Roberson]

Sorry, I lost track.

temp_matrix = [x, y];
points_not_within_range = setdiff( 1:size(temp_matrix,1), unique([idx{:}]) );
output_matrix = temp_matrix(points_not_within_range, :);

The ~ version does not work because points_within_range was a vector of indices rather than a logical vector.

[Faez Alkadi]

Thank you so much Walter its working now