X,Y cordinates in a Matrix
2 views (last 30 days)
Show older comments
Alonso Canabal
on 18 Feb 2022
Answered: Image Analyst
on 18 Feb 2022
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
0 Comments
Accepted Answer
AndresVar
on 18 Feb 2022
Loop through your points like this, although I see XY is probably very long!
A=zeros(3,3);
disp(A)
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)
0 Comments
More Answers (2)
Kevin Holly
on 18 Feb 2022
Edited: Kevin Holly
on 18 Feb 2022
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
imagesc(B)
0 Comments
Image Analyst
on 18 Feb 2022
If you need to interpolate points everywhere, see scatteredInterpolant. Demo is attached.
0 Comments
See Also
Categories
Find more on Data Distribution Plots in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!