3 dataset plot in single dimension plane

Hello there,

I have facing a problem while plotting a data set.

I have three variables,

a,b and c.

I am trying to plot c with respect to a and b.

could you please figure out this situation.

Answer 1

[Riccardo Scorretti]

Hi Suraj, you can use mesh, surf, contour and many others functions (see https://fr.mathworks.com/help/matlab/visualize/representing-a-matrix-as-a-surface.html). For instance:

[x, y] = meshgrid(0:0.05:pi, 0:0.05:1);
c = exp(-2*y).*sin(-x);
figure
surf(x, y, c);
xlabel('x') ; ylabel('y') ; zlabel('c');

[suraj karki]

Thank you for your response, Riccardo Scorretti

However, I want in 1-D.

[Riccardo Scorretti]

Ok. In 1-D you could make this:

x0 = 0:0.05:pi;
y0 = 0:0.1:1;
[x, y] = meshgrid(x0, y0);
c = exp(-2*y).*sin(-x);
figure
plot(x', c');
xlabel('x') ; ylabel('c');
lgnd = {};
for n = 1 : numel(y0)
    lgnd{n} = sprintf('y = %4.2f', y0(n));
end
legend(lgnd{:});

[Riccardo Scorretti]

Could you make a sketch of what you would like to obtain?

[suraj karki]

Sure,

For an example

c = [0.001 0.002 0.003 0.00021 0.0025]

a = [65 45 35 55 33]

b = [80 114 85 90 95]

Now, I need to plot c with respect to a and b. which means a and b have a co-relation to produce data c.

I hope you will understand this situation.

[Riccardo Scorretti]

It is still unclear to me (sorry).

Method #1: you could plot a and b as a function of c, instead of c as a function of a and b:

c = [0.001 0.002 0.003 0.00021 0.0025];
a = [65    45    35    55      33];
b = [80    114   85    90      95];
[~, ind] = sort(c);
figure
yyaxis left
plot(c(ind), a(ind), 'o-') ; xlabel('c') ; ylabel('a');
yyaxis right
plot(c(ind), b(ind), 's-') ; ylabel('b');

The information is the same, but I guess it is not what you want.

Answer 2

[Riccardo Scorretti]

Method #2: use circles of different size to represent the value of c. I hope at least it will inspire you.

c = [0.001 0.002 0.003 0.00021 0.0025];
a = [65    45    35    55      33];
b = [80    114   85    90      95];

% This parameter controls the average size of circles (just for aestetic purpose)
% I'm afraid it has to be adjusted manually depending on the number of
% points to plot and on the orders of magnitude of a and b
fact = 0.1;     

figure
sz = fact*max(abs([a(:) ; b(:)])) / max(abs(c(:)));   % = characteristic size to draw circles
sz_b = 0.01*max(abs(b));
t_ = linspace(0, 2*pi, 256);
assert(numel(a) == numel(b)  &&  numel(a) == numel(c), 'a, b, and c must have the same number of elements');
for n = 1 : numel(c)
    patch(a(n)+sz*c(n)*cos(t_), b(n)+sz*c(n)*sin(t_), 'r', ...
        'EdgeColor', 'k', 'FaceAlpha', 0.4); 
    hold on
    text(a(n), b(n)+sz*c(n)+sz_b, num2str(c(n)));
end
axis square ; box on ; grid on
xlabel('a') ; ylabel('b');