im trying to compare data sets in MatLab, and in the figure im only able to place data tips along the curve but the data set im comparing with does not match my curve (hence the comparison). Is there anyway to plot data points anywhere on the plot or do they have to be somewhere along the curve?
Any help would be appreciated.
I am not sure if I understand what you meant...
load data1.dat % your curve
load data2.dat % Comparison
figure(1)
hold
plot(data1(:,1),data1(:,2),'k-') % You plot your curve
plot(data2(:,1),data2(:,2),'ro') % you plot you points for comparison
Related
I'm trying to plot a spectrogram of a vibration signal using Matlab, but I'm not happy with the way that the spectrogram-function plots the signal (I would like to customize the axes and use a mapped vector instead of time). Right now I'm trying to plot the thing myself using pcolor:
[M_s, M_w, M_t] = spectrogram(M_i, 2^16, ceil(2^16*0.95), [0:0.2:15000], Sample_rate);
figure;
[M_t, M_w] = meshgrid(M_t, M_w);
h = pcolor(M_t, M_w, mag2db(abs(M_s)));
set(h, 'LineStyle', 'none);
However, doing this, my plotted figure is extremely slow and I can't really work with that, because it takes ages to zoom in or do anything with it. When I just use spectrogram to plot the figure, it's super fast. So my question is, what exactly does spectrogram do, to plot the figure?
I have 3D cloud of dots. I need to plot them as a surface. I tried variant with meshdrid, griddata, scatteredInterpolant,trisurf-delaunay. Nothing works. I know that this question was discussed a lot, but it seems I don't understand some important details. The code which i have now:
load('coords.mat')
figure()
subplot(1,2,1)
plot3(x,y,z,'.')
axis off
view(3)
subplot(1,2,2)
C=gray(numel(x)); % unsuccessful attempt
[~,idx]=sort(z); % to have
C=C(idx,:); % illumination
scatter3(x,y,z,50,C,'filled')
axis off
view(3)
produces the following image:
Could you help me:
1) to find a way to draw it with surface function.
and as some dots may be inside the surface (may be it is my problem)
2) How to remove 'invisible' dots?
I need solution for different cases, picture and data presents just an example.
Mat file may be downloaded here.
P.S.
In case it is important – I obtain coordinates of this dots as a rotation of random bezier curve.
UPDATE
In case data above is too big I generate another set with smaller amount of dots:
Coordinates are here.
where do you get this data from? It is represented as vectors but if you reshape it to matrices you can use the surf function. Try this code:
z=reshape(z,100,100);
y=reshape(y,100,100);
x=reshape(x,100,100);
surf(x,y,z)
I am trying to write a MATLAB script to give me a contour map. The contour map must be created from inputs that I generated from 100 images.
The story is like this:
I have 100 images on which I ran an image processing algorithm for optimization. Now, I got their energy curves. So, I have 100 energy curves. I want to create a contour map that will show me where the points are denser on the plot. (the energy curves are plotted as energy vs. iteration with fixed number of iterations)
The following is my variable:
energy(iteration,numImages)
Hope I explained it well.
Thanks in advance.
I interpret your question to boil down to how can I create a surface plot with colors according to the energy found in energy. I would solve this by using the contour function with a grid generated using meshgrid. If each image is described in 1000 data points with 100 files the plot can be generated as follows:
% using stuff as random junk instead of energy
numPoints = 1000;
numFiles = 100;
stuff = rand(1000,100); % replace with actual information
[X, Y] = meshgrid(1:numFiles, 1:numPoints);
contour(X,Y,stuff);
You can also create a 3D surface plot using surf and the same logic.
From what i see of you graph (and using the comments also), one possible way is to use plot3 to plot a line in 3D for every plot.
For doing so, you can use something like this code:
x=(0:0.01:1)';
aexp=zeros(100,numel(x));
hold on
for ii=1:100;
% aexp(ii,:)=exp((-x+ii/10)); %exponential
aexp(ii,:)=exp(-(x-ii/100).^2); %~gaussian
% aexp(ii,:)= x*ii; %linear increase
plot3(x,aexp(ii,:),ii*ones(1,numel(x)));
end
% set(gca,'yscale','log'); % uncomment if you need logscale.
giving
I have a few options of plot. It always plot from the XY view. I changed by hand, but you can use the view command. Notice that i used a simple counter to make the spacing in the z direction.
In a similar manner, you can plot using the contour. For my code, after the data have been generated in the for loop, remove/comment the plot3 and add:
contour(aexp) %outside the for loop,
giving
Notice that i have not really take care what i'm plotting. You can find more info on contour in the Matlab page .
You commented that the x-axis should be number of iterations, y-axis should be energy and z-axis should be the information containing how many lines are passing through from some areas. For this, make a qq variable, being it qq=number_of_lines(number of iterations,energy) . Make a discrete grid for the energy if you don't have one. Number of iterations is probably discrete anyway. The function is you who need to devise, but i would go for something which checks the number of lines for every energy and every iteration. In this case you will have the z-function that depends on y and x, that is the case to use contour or surface.
My function above make a line for every ii point, to have a 3d function. An edition for another extra loop is not hard. Just remember to have the same regular grid for every point, otherwise you will have trouble.
I need to plot two plots on same figure in MATLAB.
The maximum and minimum values in both the data samples have large variation, which I am unable to plot by taking same y-axis limits.
I do not wish to use two scales as explained in other Overlaying two axes in a Matlab plot but need to use a single y-axis and get the solution.
I tried the code:
x_axis_X = 1:length(S);
y_axis_Y = 1:length(N);
ylim([-1204200 -1841.6])
set(gcf,'color','w');
plot(x_axis_X, S,'o-', y_axis_Y, N, 'x-');
The result is as shown in the plot where one data sample is plotted without proper y-axis range.
The y limits for first data sample is -1204200 to -1841.6 and for the second it is -489429345.5 to -10408189.43.
How should be the ylim defined to fit both plots in the same figure?
I appreciate your inputs. Thank you.
In older versions of MATLAB use the function plotyy. In more recent versions of MATLAB use yyaxis. The following is the example from the documentation:
x = linspace(0,10);
y = sin(3*x);
yyaxis left
plot(x,y)
z = sin(3*x).*exp(0.5*x);
yyaxis right
plot(x,z)
ylim([-150 150])
I tried the idea of scaling one dataset so that it has a similar magnitude as the other data set. Here, I multiplied one dataset by 100 (or any suitable scaling parameter), and then it will be similar in size to the other data set. In order to clearly mention which data has been scaled in the graph I used the legend.
plot(x,data1,x,100*data2)
legend('data1','100*data2','location','southeast')
Thank you.
Scaling is not the best option, as you may need to work with the data later. Also does not work if for instance, you need a log scale.
Matlab has a few ways to deal it with. I particularly like to use a new axes in the figure, as i have done in the example below.
Just in case, you also found this answer in a simple google search!
Code:
a=1:10;
b=(10:-1:1)*100;
x=1:10;
hold on
plot(x,a,'b')
pax1=get(gca,'Position'); %get axis position
ax2 = axes('Position',pax1); %create a new axis
plot(ax2,x,b,'r') %plot new data
set(ax2, 'Yaxislocation','right',...
'color','none') % set it transparent and to the right
I am new to MATLAB. I have 2 functions,z=sin(x) and
y=cos(x). I want to plot them in a 3D (x,y,z) chart (but not with subplot), z=sin(x) in plane X-Z and y=cos(x) in plane X-Y. As I have seen, standard plot or plot3d functions are not obvious to use. May be needed some axis manipulation, etc, but I don't have it.
I would like to know the solution if only I would or any guidance is appreciated.
Here you have a small example of what you want to do
clear;clc; %clear variables from workspace and clean commadn line
x=-pi:0.1:pi; %define x
cero=zeros(size(x)); %create a vector of zeros
z=sin(x);
y=cos(x);
hold on %tell matlab to plot averything together
plot3(x,cero,z,'g');
plot3(x,y,cero,'r');
grid on; %pretty self-describing
view([1,1,1]) %set viewpoint to not se just a plane
hold off %stop ploting everything together
Ask if you don't get some of the lines