X,Y cordinates in a Matrix

Hi, In an effort to create a heatmap y want to convert a list of X,Y coordinates to a 2D matrix. If a point x,y belongs to a point in the matrix a 1 should appear, is more than one point belong into a single matrix coordinate, the number of the points should appear.

A handmade example

A =

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

>> XY

XY =

1 3 5 2 3

1 4 2 2 4

>> B

B =

1 0 0 0 0

0 1 0 0 1

0 0 0 0 0

0 0 2 0 0

0 1 0 0 0

This is to create a high resolution nice heatmaps with a ton of numbers. Thank you very much

Answer 1

[AndresVar]

Loop through your points like this, although I see XY is probably very long!

A=zeros(3,3);
disp(A)

     0     0     0
     0     0     0
     0     0     0

B=[1 1 1;
    1 3 3];
for ii = 1:size(B,2)
   A(B(1,ii),B(2,ii))=A(B(1,ii),B(2,ii))+1;
end
disp(A)

     1     0     2
     0     0     0
     0     0     0

Answer 2

[Kevin Holly]

A = [0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0
     0     0     0     0     0];

XY = [1     3     5     2     3
     1     4     2     2     4];

B=A;
for i = 1:length(XY)
A(XY(2,i),XY(1,i))= 1;
B = B + A;
A=zeros(5);
end

B

B = 5×5

1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0

imagesc(B)

Answer 3

[Image Analyst]

If you need to interpolate points everywhere, see scatteredInterpolant. Demo is attached.