Finding the nearest neighbor to a single point in MATLAB

Question

I\'m trying to do a nearest neighbor search that yields a single point as the single \"nearest neighbor\" to another point in matlab.

I\'ve got the following data:

Answer 1

If you're working without Toolboxes, you can construct a simple distance formula yourself:

xx = [0:364];  % Not sure what your limits were so just making some up here
yy = [0:264];
[X, Y] = meshgrid(xx,yy);
dxf = [221.7, 109.1];  % Again just pulling numbers from nether regions 

G = [X(:),Y(:)];
d = sqrt( sum( (G-dxf).^2, 2) );
[minDist, idxMinDist] = min(d);
solution = G(idxMinDist,:);

You can modify the limits for xx and yy to fit your specific setup accordingly.

Answer 2

You should first convert your grid to an n-by-2 matrix (if you created this using meshgrid, it's simply G = [XX(:) YY(:)]), you can then try it with pdist2 if you have the Statistics and Machine Learning Toolbox (which you do):

[D,I] = pdist2(P, G, 'euclidian', 'Smallest', 1);

Where G is the grid and P is your m-by-2 array of points to test.