Get bin label associated with 2D histogram of x,y data
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Hello,
I am looking for a way to extract the bin labels from a large matrix of x and y coordinates. So the basic form of it would look like this:
A(:,1) = randi([50 550],500,1); % random x coord
A(:,2) = randi([50 250],500,1); % random y coord
Hist = hist3(A, [25 25]);
Is it possible to get the bin label associated with each of my 500 datapoints? Bigger picture is that all these coordinates in fact have some value and I want to average all these values for the bin they were found in based on their coordinates, before processing them further. Thanks for any help/advice!
J
edit: no I don't want the count of the number of coords in each bin, I need the bin label (say i,j and running from 1,1 to 25,25) of each pair of coordinates x,y. Hope this makes sense... thanks!
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Doug Hull
on 21 Feb 2013
By Bin label, do you mean the count of the number of data points in each bin? Please edit your originial question to clarify.
Answers (1)
Sean de Wolski
on 21 Feb 2013
Yea, you'll be able to do this using histc() and accumarray():
x = ceil(rand(1000,1)*10); %x
y = ceil(rand(1000,1)*10); %y
z = rand(1000,1); %values
edges = 1:10; %some edges to bin along
[~, idxx] = histc(x,edges); %Which x bin?
[~, idxy] = histc(y,edges); %Which y bin?
averages = accumarray([idxx idxy],z,[],@mean); %Build the average matrix
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