Converting a matrix of points to a list of x & y coordinates

Hello,

I have a matrix of size n*n, filled with zeros. Some points are filled with A's. I'd like to take this matrix and turn it into two arrays, one with the x-coordinates of each A and the other with the y-coordinates of each A.

I have seen numerous ways of going the other way, i.e. from a list of coordinates to a matrix, but none going this way.

Any help is greatly appreciated!

[Douglas]

The reason I am looking to do this is to be able to use the scatter(X,Y) function to plot a sort of map of the matrix I have.

Is there perhaps a better way to do this?

Answer 1

[Guillaume]

Use the two arguments output of find (rather than find + ind2sub):

[y, x] = find(matrix);

[Douglas]

I went with this, seems the most straight-forward. Thank you!

Answer 2

[Iain]

 Index_of_As = find( matrix );
 [down along] = ind2sub(size(matrix),Index_of_As);

Answer 3

[Adam]

ind1d = find( myMatrix == 'A' );

[y, x] = ind2sub( [n n], ind1d );

should be close to doing the job, although it depends what you mean by 'A'. Do you have a cell array? The above code would work if, instead of 'A', you had some numerical value, but otherwise it would likely need a bit of syntactical modification depending if you have a cell array.