I'm trying to plot 2 lines in a single 3D graph. I have 3 coordinate data matrices for each line.
This is my code:
plot3(pathline_x1 , pathline_y1 , pathline_z1,'g');
hold on
plot3(pathline_x1,pathline_y1,pathline_z1,'r');
hold on
From some reason it plots only the last one. Can someone help me plot both lines?
x = [1 2];y=x;
figure;plot(x,y,'r');hold on;plot(x,y,'b');
This will overwrite your line, since x and y are exactly equal.
To see it actually works, plot two different lines:
figure;plot(x,y,'r');hold on;plot(x,y+2,'b');
Note that I have called hold on only once, since it will hold all plots within the figure until you call hold off or open a new figure using figure.
Related
This question is quite basic, but I am looking for the best way to do this.
For a plotted line in matlab, how can a few points on the line be marked. I know it is possible to plot directly using marks. But, in case the line has been plotted and the marks are just to differentiate the plots. Instead of selecting a few points and plotting the second time. An example is shown in this figure below
Right after creating the initial plot you can use the command 'hold on' to keep that plot 'live' and then replot the points as markers. For example:
x=1:10;
y=2*x+4;
plot(x,y)
hold on
plot(x,y,'+')
You can use '*', '.' or any other marker instead of '+'.
If you want the markers to be evenly spaced (and your data is not ,originally) you may create an evenly spaced x vector and then, assuming your plot is not too extreme, interpolate the y values and add just the points. For example:
x=[1,1.5,2,2.3,3,4,4.8,5,6.1,6,7,8,9,10];
y=2*x.^2+4;
plot(x,y)
hold on
x_lin=linspace(min(x),max(x),20);
y_lin=interp1(x,y,x_lin,'linear');
plot(x_lin,y_lin,'+')
hold off
With the following result:
If 'linear' doesn't give a good enough result you can try other interpolation methods like 'cubic', 'spline'...
If you don't want to "add" the marked points in a second moment (but I don't think you will have some advantage), consider to
A) use two plot instructions, separating the array of points "to be marked" using
C = setdiff(A,B)
alternatively
B) plot every point in a for cycle with counter i under a condition
%not tested solution
c1 = '.r' %red point, if they are near they seems a line
c2 = '*b' %blue marker
if (marker_condition == true)
plot(x(i), y(i), c2)
else
plot(x(i), y(i), c1)
end
I have two graphs, one is the exact graph of a solution, the other is a numerical approach. I have 4 specific points in my figure (t=0.25,0.5,0.75,1), where I want to illustrate the difference between the two graphs with a straight line. I found the errorbars function but i don't see any use there. Hope you can help me!
Edit:
this is the example figure:
t = [0:0.25:1];
y = t.*4;
x = t.^2+3;
plot(t,y,t,x)
I have 4 points now, t=0.25; t=0.5; t=0.75; t=1; At this points, I just want a vertical line between the two plots. I already have tried this: plot([t(1),y(1)],[t(1),x(1)])
but it just creates a line over the whole figure.
✶ It seems that you're not using hold on before using plot command the second time because otherwise you'd have got the desired result (which is actually not a correct way of plotting a vertical line).
✶ You're mixing up the values of x and y for plot(x,y). To plot a vertical line, it should be used like this: plot([x,x], [y1,y2])
For your case, you may not notice the difference between plot([t(1),y(1)],[t(1),x(1)]) (which is incorrect) and plot([t(1),t(1)],[x(1),y(1)]) (which is correct) because it is by chance that the values are same. Plot it for some other points and you'll realize the difference.
Fixed Code:
t = [0:0.25:1];
y = t.*4;
x = t.^2+3;
plot(t,y,t,x)
hold on
plot([t(1) t(1)],[x(1) y(1)])
% You have 't' on your horizontal axis and 'x'and 'y' values on the vertical axis
axis equal % just for better visualization
Output:
I want to create a 3x3 matrix of plots in MATLAB where each element is a subplot of some corresponding 1000 samples (suppose values are stored in a 3x3x1000 matrix A). I want the subplots to be spaced very close together, and the y axis numbers/labels to only show up for the left subplots and the x axis numbers/labels to only show up for the bottom subplots.
For example, something similar to plotmatrix, except subplot ij would plot A(i,j,:).
plotmatrix example
Is there an easy way to do this in MATLAB? Thanks!
The axes properties of the subplots can be modified to achieve this, but an easier way would be to use a FEX submission called panel. Have a look at its example output:
subplot can do that for you in MATLAB.
h = subplot(3,3,1)
Will split the current figure in a 3 x 3 matrix and creates an axes(area where you plot something) in the 1st cell of the matrix. h is the "handle" to the axes which you can then use to modify the xlabels and ylabels in any way.
Documentation for subplot
Documentation for Axes
I have two two-by-n arrays, representing 2d-points. These two arrays are plotted in the same figure, but in two different subplots. For every point in one of the arrays, there is a corresponding point i the other array. I want to show this correspondance by drawing a line from one of the subplots to the other subplot.
The solutions i have found are something like:
ah=axes('position',[.2,.2,.6,.6],'visible','off'); % <- select your pos...
line([.1,.9],[.1,.9],'parent',ah,'linewidth',5);
This plots a line in the coordinate system given by the axes call. In order for this to work for me i need a way to change coordinate system between the subplots system and the new system. Anybody know how this can be done?
Maybe there is different way of doing this. If so i would love to know.
First you have to convert axes coordinates to figure coordinates. Then you can use ANNOTATION function to draw lines in the figure.
You can use Data space to figure units conversion (ds2nfu) submission on FileExchange.
Here is a code example:
% two 2x5 arrays with random data
a1 = rand(2,5);
a2 = rand(2,5);
% two subplots
subplot(211)
scatter(a1(1,:),a1(2,:))
% Convert axes coordinates to figure coordinates for 1st axes
[xa1 ya1] = ds2nfu(a1(1,:),a1(2,:));
subplot(212)
scatter(a2(1,:),a2(2,:))
% Convert axes coordinates to figure coordinates for 2nd axes
[xa2 ya2] = ds2nfu(a2(1,:),a2(2,:));
% draw the lines
for k=1:numel(xa1)
annotation('line',[xa1(k) xa2(k)],[ya1(k) ya2(k)],'color','r');
end
Make sure your data arrays are equal in size.
Edit: The code above will do data conversion for a current axes. You can also do it for particular axes:
hAx1 = subplot(211);
% ...
[xa1 ya1] = ds2nfu(hAx1, a1(1,:),a1(2,:));
A simple solution is to use the toolbar in the figure window. Just click "insert" and then "Line".
How do you get rid of the axes and dotted line grids when you plot in Matlab? Also, how do I make subplots of subplots. Since that's probably not very clear, what I mean is the following...
Let's say I have a 10x10x10 .mat file, so I open each of the 10 frames and plot what I have on each 10x10 frame. I generate 2 different plots for each frame so that in total there are 20 plots. For each frame I generate 2 subplots. When I run the code, I get 10 different figures with 10 subplots. I'd like to get for this example 1 figure with 20 subplots where the first two refer to the first iteration, second two refer to the second, etc.
for i = 1:10
z=z(:,:,i);
figure(i)
subplot(1,2,1)
surf(z)
%code, obtain new array...
subplot(1,2,2)
surf(new)
end;
You can hide the axes with
set(gca,'Visible','off')
And if you want 20 subplots, try the following:
for i = 1:10
z=z(:,:,i);
subplot(10,2,2*i-1)
surf(z)
%code, obtain new array...
subplot(10,2,2*i)
surf(new)
end
When you use figure(i), you're referring to Figure i which will be created if it does not exist. And with subplot you can specify the ordering of the subplots with the first two arguments.
Note:
20 subplots on one figure are not going to be pretty --- you probably won't be able to see anything, so you should probably break it up into several figures.