Matlab: Plot3 not showing the 3rd axis
Вопрос
All the three variables I am using to plot are matrix of size 1x1x100
. I am using this code line to plot:
hold on;
for i=1:100
plot3(R_L(:,:,i),N_Pc(:,:,i),CO2_molefraction_top_of_window(:,:,i),'o');
xlabel('R_L');
ylabel('N_P_c');
zlabel('CO_2')
end
However, I am not getting the third axis, and hence the third variable CO2_molefraction_top_of_window
on the plot. May I know where am I wrong?
Besides the above question, but on the same subject, I want to know if there is any option where I can plot 4 dimensional plot just like the 3 dimensional plot which can be drawn using plot3
?
Решение
Just a note --- you only need to do the xlabel
ylabel
zlabel
commands once (outside the loop).
Also:
- is there any reason your matrices are
1x1x100
instead of just100x1
or1x100
? Because if you reshape them to 2D you can just do the plotting in one hit. - What do you mean by "missing third axis"? When I run your code (or as close as I can get, since you didn't provide a reproducible example), I do get a 3rd axis:
.
X = rand(1,1,100); % 1x1x100 X matrix
Y = rand(1,1,100); % 1x1x100 Y matrix
Z = rand(1,1,100); % 1x1x100 Z matrix
% Now, we could do a for loop and plot X(:,:,i), Y(:,:,i), Z(:,:,i),
% OR we can just convert the matrix to a vector (since it's 1x1x100 anyway)
% and do the plotting in one go using 'squeeze' (see 'help squeeze').
% squeeze(X) converts it from 1x1x100 (3D matrix) to 100x1 (vector):
plot3(squeeze(X),squeeze(Y),squeeze(Z),'o')
xlabel('x')
ylabel('y')
zlabel('z')
This gives the following, in which you can clearly see three axes:
If it's the gridlines that you want to make the graph look "more 3D", then try grid on
(which is in the examples in the Matlab help file for plot3
, try help plot3
from the Matlab prompt):
grid on
You will have to clarify "missing third axis" a bit more.
Другие советы
So I had the same problem when using plot3
. For some reason, using the hold on
command "flattens" the plot. I'm not sure why, but I suspect it has something to do with the operation hold on
performs on the plot.
Edit: To clarify, the 3d plot is still there, but the perspective has been forced to change. If you use the "rotate 3D" tool (the one with an arrow around a cube), you can see the graph is 3d, the default perspective is just straight on so only two axes are visible and it appears flat.
I came across a similar problem and as @Drofdarb's the hold on
seems to flatten out one axis. Here is a snippet of my code, hope this helps.
for iter = 1:num_iters:
% hold on;
grid on;
plot3(tita0,tita1, num_iters,'o')
title('Tita0, Tita1')
xlabel('Tita0')
ylabel('Tita1')
zlabel('Iterations')
hold on; % <---- Place here
drawnow
end
As opposed to:
for iter = 1:num_iters:
grid on;
hold on; % <---- Not here
plot3(tita0,tita1, num_iters,'o')
title('Tita0, Tita1')
xlabel('Tita0')
ylabel('Tita1')
zlabel('Iterations')
% hold on;
drawnow
end