Finding the minimum values from a scatter graph ?

First, I plotted all the values I found together as a scatter. I have used the hold on function in this file. Now what I want from Matlab is all the lowest Y values for one X value (Also optimum curve). For e.g. see second image the doted line is what I want from my first set of data, but i cannot use min(Sample) function to get my values as the points are not really the minimums of each individual curves.

Need to find the optimum curve from the below graph.

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Answer 1

[Walter Roberson]

Let X{K} be the X values for curve #K, and let Y{K} be the corresponding Y values. In the following I will take advantage of the fact that I have used cell arrays.

allX = [X{:}];
allY = [Y{:}];
[uX, aidx, bidx] = unique(allX);
minY = accumarray( bidx(:), allY(bidx), [], @min );

scatter( uX, minY )