I have a 3-dimensional data to be plotted in matlab. The data set are built by stacking 10 exponential curves with different parameters along y directions such as
x = 0:0.01:15;
x0 = 0.5;
y = [beta1, beta2, beta3, beta4, beta5, beta6, beta7, beta8, beta9, beta10];
Z(1, :) = A*exp(-(x-x0).^2/beta1);
Z(2, :) = A*exp(-(x-x0).^2/beta2);
Z(3, :) = A*exp(-(x-x0).^2/beta3);
Z(4, :) = A*exp(-(x-x0).^2/beta4);
...
Z(10, :) = A*exp(-(x-x0).^2/beta10);
% here A could be change based on beta too (no code shown here)
I am trying to plot Z with waterfall except for I don't want the height (i.e. the vertical line) appears on the edge. I don't know if there is any other way to plot the data as waterfall-like curves but without those vertical lines. Thanks
"it is plotted with lines instead of patch with surface".
In other words, you want the boundary lines to be invisible. Well that's no trivial feat as the boundary lines are separate from any color scheme you can directly include. What you need to do is get the data after it drawn then modify it accordingly:
e.g.
[X,Y,Z] = peaks(30);
h = waterfall (X,Y,Z);
CD = get (h, 'CData');
CD(1,:) = nan;
CD(end-2:end,:) = nan;
set (h, 'CData', CD)
note that CD(1,:) is for the "rising" boundary, while CD(end-2:end-1,:) is for the falling boundary, and CD(end,:) is for the bottom.
i know this is an old post, but the below will make the region under the curve transparent:
figure;
[X,Y,Z] = peaks(10);
handle_figure = waterfall( X, Y, Z );
set( handle_figure, 'FaceColor', 'none' );
Related
I am trying to plot two different ellipses in Matlab with the same foci. Essentially I am plotting the elliptical orbit before and after an impulse maneuver.
The first (before maneuver) ellipse will always be in-line with the x-axis, whereas the second ellipse (after maneuver) will be at an angle above/below the x-axis (The second one will have a different major/minor axis and eccentricity as well).
In order to save space, the code for plotting one ellipse will be the same as the second ellipse, so I'll only show my code here for plotting one ellipse.
The problem is that it plots from the center of the grid, and not the foci.
Re = 6378.136; %km
e = .65;
x1 = -4.4*Re; %-a
x2 = 4.4*Re; % a
y1 = 0;
y2 = 0;
a = 1/2*sqrt((x2-x1)^2+(y2-y1)^2);
b = a*sqrt(1-e^2);
t = linspace(0,2*pi);
X = a*cos(t);
Y = b*sin(t);
w = atan2(y2-y1,x2-x1);
x = (x1+x2)/2 + X*cos(w) - Y*sin(w);
y = (y1+y2)/2 + X*sin(w) + Y*cos(w);
plot(x,y,'b')
axis equal
grid on
hold on
I'm sure it's something simple but I can't seem to figure it out.
Any help is much appreciated. Thanks.
Edit: David helped solve this issue, thank you.
I've found this answer, but I can't complete my work. I wanted to plot more precisely the functions I am studying, without overcoloring my function with black ink... meaning reducing the number of mesh lines. I precise that the functions are complex.
I tried to add to my already existing code the work written at the link above.
This is what I've done:
r = (0:0.35:15)'; % create a matrix of complex inputs
theta = pi*(-2:0.04:2);
z = r*exp(1i*theta);
w = z.^2;
figure('Name','Graphique complexe','units','normalized','outerposition',[0.08 0.1 0.8 0.55]);
s = surf(real(z),imag(z),imag(w),real(w)); % visualize the complex function using surf
s.EdgeColor = 'none';
x=s.XData;
y=s.YData;
z=s.ZData;
x=x(1,:);
y=y(:,1);
% Divide the lengths by the number of lines needed
xnumlines = 10; % 10 lines
ynumlines = 10; % 10 partitions
xspacing = round(length(x)/xnumlines);
yspacing = round(length(y)/ynumlines);
hold on
for i = 1:yspacing:length(y)
Y1 = y(i)*ones(size(x)); % a constant vector
Z1 = z(i,:);
plot3(x,Y1,Z1,'-k');
end
% Plotting lines in the Y-Z plane
for i = 1:xspacing:length(x)
X2 = x(i)*ones(size(y)); % a constant vector
Z2 = z(:,i);
plot3(X2,y,Z2,'-k');
end
hold off
But the problem is that the mesh is still invisible. How to fix this? Where is the problem?
And maybe, instead of drawing a grid, perhaps it is possible to draw circles and radiuses like originally on the graph?
I found an old script of mine where I did more or less what you're looking for. I adapted it to the radial plot you have here.
There are two tricks in this script:
The surface plot contains all the data, but because there is no mesh drawn, it is hard to see the details in this surface (your data is quite smooth, this is particularly true for a more bumpy surface, so I added some noise to the data to show this off). To improve the visibility, we use interpolation for the color, and add a light source.
The mesh drawn is a subsampled version of the original data. Because the original data is radial, the XData and YData properties are not a rectangular grid, and therefore one cannot just take the first row and column of these arrays. Instead, we use the full matrices, but subsample rows for drawing the circles and subsample columns for drawing the radii.
% create a matrix of complex inputs
% (similar to OP, but with more data points)
r = linspace(0,15,101).';
theta = linspace(-pi,pi,101);
z = r * exp(1i*theta);
w = z.^2;
figure, hold on
% visualize the complex function using surf
% (similar to OP, but with a little bit of noise added to Z)
s = surf(real(z),imag(z),imag(w)+5*rand(size(w)),real(w));
s.EdgeColor = 'none';
s.FaceColor = 'interp';
% get data back from figure
x = s.XData;
y = s.YData;
z = s.ZData;
% draw circles -- loop written to make sure the outer circle is drawn
for ii=size(x,1):-10:1
plot3(x(ii,:),y(ii,:),z(ii,:),'k-');
end
% draw radii
for ii=1:5:size(x,2)
plot3(x(:,ii),y(:,ii),z(:,ii),'k-');
end
% set axis properties for better 3D viewing of data
set(gca,'box','on','projection','perspective')
set(gca,'DataAspectRatio',[1,1,40])
view(-10,26)
% add lighting
h = camlight('left');
lighting gouraud
material dull
How about this approach?
[X,Y,Z] = peaks(500) ;
surf(X,Y,Z) ;
shading interp ;
colorbar
hold on
miss = 10 ; % enter the number of lines you want to miss
plot3(X(1:miss:end,1:miss:end),Y(1:miss:end,1:miss:end),Z(1:miss:end,1:miss:end),'k') ;
plot3(X(1:miss:end,1:miss:end)',Y(1:miss:end,1:miss:end)',Z(1:miss:end,1:miss:end)','k') ;
Question
When using polarhistogram(theta) to plot a dataset containing azimuths from 0-360 degrees. Is it possible to specify colours for given segments?
Example
In the plot bellow for example would it be possible to specify that all bars between 0 and 90 degrees (and thus 180-270 degrees also) are red? whilst the rest remains blue?
Reference material
I think if it exists it will be within here somewhere but I am unable to figure out which part exactly:
https://www.mathworks.com/help/matlab/ref/polaraxes-properties.html
If you use rose, you can extract the edges of the histogram and plot each bar one by one. It's a bit of a hack but it works, looks pretty and does not require Matlab 2016b.
theta = atan2(rand(1e3,1)-0.5,2*(rand(1e3,1)-0.5));
n = 25;
colours = hsv(n);
figure;
rose(theta,n); cla; % Use this to initialise polar axes
[theta,rho] = rose(theta,n); % Get the histogram edges
theta(end+1) = theta(1); % Wrap around for easy interation
rho(end+1) = rho(1);
hold on;
for j = 1:floor(length(theta)/4)
k = #(j) 4*(j-1)+1; % Change of iterator
h = polar(theta(k(j):k(j)+3),rho(k(j):k(j)+3));
set(h,'color',colours(j,:)); % Set the color
[x,y] = pol2cart(theta(k(j):k(j)+3),rho(k(j):k(j)+3));
h = patch(x,y,'');
set(h,'FaceColor',colours(j,:),'FaceAlpha',0.2);
uistack(h,'down');
end
grid on; axis equal;
title('Coloured polar histogram')
Result
I need to make a plot with a discrete colorbar in Matlab. I do this in the following way:
data = randi(10, 20);
imagesc(data)
my_colormap = rand(10, 3);
colormap(my_colormap)
cb = colorbar
set(cb,'YTickLabel',{'A';'B';'C';'D';'E';'F';'G';'H';'I';'J';})
Now my problem is that the colorbar tick labels and the small lines in the colorbar don't align nicely. How can I even the colorbar tick labels and the small lines better as illustrated in the following pic:
The TickLabel on the colorbar each correspond to a value (a Tick). To place the TickLabels in the middle, you need to place the tick in the middle. To make this dynamic (so that It does not change when resizing the image) was I bit tricky I recall and I do not really recall. To set the ticks just once is not so hard though,
set(hCbar,'YTicks',RightYTicks);
EDIT:
On request I will post an example. This should give a hint of what to do.
x = 1:10;
y = 1:10;
cmap = jet(10);
[x, y] = meshgrid(x,y); %x and y grid
c = x-0.1; %Set color code to increase to the right
hFig = figure;
scatter(x(:),y(:),10,c(:),'filled'); % Simpler for the example
set(gca(hFig),'CLim',[0,10]);
colormap(cmap);
hCbar = colorbar;
set(hCbar,'YTicks',0.5:9.5);
set(hCbar,'YTickLabels',{'A','B','C','D','E','F','G','H','I','J'});
For newer matlab version, the YTicks may have changed name to Ticks And YTickLabels may be called TickLabels.
I have a 3-dimensional data to be plotted in matlab. The data set are built by stacking 10 exponential curves with different parameters along y directions such as
x = 0:0.01:15;
x0 = 0.5;
y = [beta1, beta2, beta3, beta4, beta5, beta6, beta7, beta8, beta9, beta10];
Z(1, :) = A*exp(-(x-x0).^2/beta1);
Z(2, :) = A*exp(-(x-x0).^2/beta2);
Z(3, :) = A*exp(-(x-x0).^2/beta3);
Z(4, :) = A*exp(-(x-x0).^2/beta4);
...
Z(10, :) = A*exp(-(x-x0).^2/beta10);
% here A could be change based on beta too (no code shown here)
I am trying to plot Z with waterfall except for I don't want the height (i.e. the vertical line) appears on the edge. I don't know if there is any other way to plot the data as waterfall-like curves but without those vertical lines. Thanks
"it is plotted with lines instead of patch with surface".
In other words, you want the boundary lines to be invisible. Well that's no trivial feat as the boundary lines are separate from any color scheme you can directly include. What you need to do is get the data after it drawn then modify it accordingly:
e.g.
[X,Y,Z] = peaks(30);
h = waterfall (X,Y,Z);
CD = get (h, 'CData');
CD(1,:) = nan;
CD(end-2:end,:) = nan;
set (h, 'CData', CD)
note that CD(1,:) is for the "rising" boundary, while CD(end-2:end-1,:) is for the falling boundary, and CD(end,:) is for the bottom.
i know this is an old post, but the below will make the region under the curve transparent:
figure;
[X,Y,Z] = peaks(10);
handle_figure = waterfall( X, Y, Z );
set( handle_figure, 'FaceColor', 'none' );