Ceate a x b matrix (or 2D array) from 2 1Darrays, and populate each cell from another array
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So I have 3 arrays; say a,b,c. a and b represent distances, and c represents a variable with a specific value at the point (a,b).
I have been trying to create a matrix which comprises of (b x a) cells, and the populate it with the values of c, in order to then image, heatmap it etc.
However the issue I have having is that there are many repeating values of a and b; a stays fixed and it then iterates across all values of b, then moves onto the next value of a, and so forth. The range of a and b is fixed and always iterate across equally spaced values though.
Below is the code I have created for this. So for it seems to not to work and I am out of ideas.
z_true_len = length(unique(a)); %number of z distances
r_true_len = length(unique(b)); %number of r disatances
data_matrix = zeros(r_true_len,z_true_len); %create r x z matrix, full of 0s
z_past = 0;
r_past = 0;
z_count = 1;
r_count = 1;
for count = 1: length(a)
z_current = a(count);
if z_past ~= z_current
data_matrix(1:z_count) = c(count);
z_past = z_current;
z_count = z_count + 1;
r_count = 1;
else
data_matrix(r_count:z_count) = c(count);
r_count = r_count + 1;
end
end
data_matrix
I have also tried the simplier:
a = [1 1 1 1 2 2 2 2 3 3 3 3];
b = [1 2 3 4 1 2 3 4 1 2 3 4];
c = [0 2 1 0 0 4 6 8 4 2 0 0];
z_true_len = length(unique(a));
r_true_len = length(unique(b));
data_matrix = zeros(r_true_len,z_true_len);
for count = 1:length(a),
data_matrix(b(count),a(count)) = c(count);
end
figure;
imagesc(data_matrix)
However this will only work if a,b and c contatin interger values, which sadly they do not.
0 Comments
Answers (1)
Ahmet Cecen
on 14 Aug 2014
Edited: Ahmet Cecen
on 14 Aug 2014
[X,Y] = meshgrid(xgv,ygv)
is your friend.
You can also do it another way, let say your x range is 1 to 5 and y range is 1 to 6, and I am also assuming x goes 1 1 1 1 1 1 while y goes 1 2 3 4 5 6 and so on:
X=reshape(x,[6 5]);
Y=reshape(y,[6 5]);
C=reshape(c,[6 5]);
surf(X,Y,C);
7 Comments
Ahmet Cecen
on 14 Aug 2014
I would avoid trying to edit it programmatically. Use the GUI after surf to modify the colors, axes etc, then use file->generate code to spit out a function that will have your visual modifications coded in automatically. You would then use the new function to plot subsequent results.
Check:
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