I have 3 arrays,
y = [1,4,6,8,2,5,......];
x = [1,2,3,4,5,6,......];
xlabel = {'label1','label2','label3',........};
where each element in xlabel is the label for each element of the x array.
I am plotting this using:
plot(x,y);
set(gca,'xtick',x,'xticklabel',xlabel);
But because my arrays hold thousands of elements I am getting a black bar as a label because MATLAB is printing every label (see image).
How do I change this so MATLAB only prints a select few of my xlabels?
You can do for example:
selected = 1:100:numel(x); % change the "100" as desired
set(gca,'xtick',x(selected),'xticklabel',xlabel(selected));
Related
I produced a plot that contains 50 curves and each of them corresponds to a specific value of a parameter called "Jacobi constant", so I have 50 values of jacobi constant stored in array called jacobi_cst_L1:
3.000900891023230
3.000894276927840
3.000887643313580
3.000881028967010
3.000874419173230
3.000867791975870
3.000861196034850
3.000854592397690
3.000847948043080
3.000841330136040
3.000834723697250
3.000828099771820
3.000821489088600
3.000814922863360
3.000808265737810
3.000801695858850
3.000795067776960
3.000788475204760
3.000781845363950
3.000775192199620
3.000768609354090
3.000761928862980
3.000755335851910
3.000748750854930
3.000742084743060
3.000735532899990
3.000728906460450
3.000722309400740
3.000715644446600
3.000709016645110
3.000702431180730
3.000695791284050
3.000689196186970
3.000682547292110
3.000675958537960
3.000669315388860
3.000662738391370
3.000656116141060
3.000649560630930
3.000642857256680
3.000636330415510
3.000629657944820
3.000623060310100
3.000616425935580
3.000609870077710
3.000603171772120
3.000596554947660
3.000590018845460
3.000583342259840
3.000576748353570
I want to use a colormap to color my curves and then show in a lateral bar the legend that show the numerical values corresponding to each color of orbit.
By considering my example image, I would want to add the array of constants in the lateral bar and then to color each curve according the lateral bar.
% Family of 50 planar Lyapunov orbits around L1 in dimensionless unit
fig = figure;
for k1 = 1:(numel(files_L1_L2_Ly_prop)-2)
plot([Ly_orb_filt(1).prop(k1).orbits.x],[Ly_orb_filt(1).prop(k1).orbits.y],...
"Color",my_green*1.1); hold on %"Color",my_green*1.1
colorbar()
end
axis equal
% Plot L1 point
plot(Ly_orb_filt_sys_data(1).x,Ly_orb_filt_sys_data(1).y,'.',...
'color',[0,0,0],'MarkerFaceColor',my_green,'MarkerSize',10);
text(Ly_orb_filt_sys_data(1).x-0.00015,Ly_orb_filt_sys_data(1).y-0.0008,'L_{1}');
%Primary bodies plots
plot(AstroData.mu_SEM_sys -1,0,'.',...
'color',my_blue,'MarkerFaceColor',my_blue,'MarkerSize',20);
text(AstroData.mu_SEM_sys-1,0-0.001,'$Earth + Moon$','Interpreter',"latex");
grid on;
xlabel('$x$','interpreter','latex','fontsize',12);
ylabel('$y$','interpreter','latex','FontSize',12);
How can I color each line based on its Jacobi constant value?
You can use any colour map to produce a series of RGB-triplets for the plotting routines to read (Or create an m-by-3 matrix with elements between 0 and 1 yourself):
n = 10; % Plot 10 lines
x = 1:15;
colour_map = jet(n); % Get colours. parula, hsv, hot etc.
figure;
hold on
for ii = 1:n
% Plot each line individually
plot(x, x+ii, 'Color', colour_map(ii, :))
end
colorbar % Show the colour bar.
Which on R2007b produces:
Note that indexing into a colour map will produce linearly spaced colours, thus you'll need to either interpolate or calculate a lot to get the specific ones you need. Then you can (need to?) modify the resulting colour bar's labels by hand to reflect your input values. I'd simply use parula(50), treat its indices as linspace(jacobi(1), jacobi(end), 50) and then my_colour = interp1(linspace(jacobi(1), jacobi(end), 50), parula(50), jacobi).
So in your code, rather than using "Color",my_green*1.1 for each line, use "Color",my_colour(kl,:), where my_colour is whatever series of RGB triplets you have defined.
I want to plot a confusion matrix in MATLAB. Here's my code;
data = rand(3, 3)
imagesc(data)
colormap(gray)
colorbar
When I run this, a confusion matrix with a color bar is shown. But usually, I have seen confusion matrix in MATLAB will give counts as well as probabilities. How can I get them? How can I change the class labels which will be shown as 1,2,3, etc.?
I want a matrix like this:
If you do not have the neural network toolbox, you can use plotConfMat. It gets you the following result.
I have also included an independent example below without the need for the function:
% sample data
confmat = magic(3);
labels = {'Dog', 'Cat', 'Horse'};
numlabels = size(confmat, 1); % number of labels
% calculate the percentage accuracies
confpercent = 100*confmat./repmat(sum(confmat, 1),numlabels,1);
% plotting the colors
imagesc(confpercent);
title('Confusion Matrix');
ylabel('Output Class'); xlabel('Target Class');
% set the colormap
colormap(flipud(gray));
% Create strings from the matrix values and remove spaces
textStrings = num2str([confpercent(:), confmat(:)], '%.1f%%\n%d\n');
textStrings = strtrim(cellstr(textStrings));
% Create x and y coordinates for the strings and plot them
[x,y] = meshgrid(1:numlabels);
hStrings = text(x(:),y(:),textStrings(:), ...
'HorizontalAlignment','center');
% Get the middle value of the color range
midValue = mean(get(gca,'CLim'));
% Choose white or black for the text color of the strings so
% they can be easily seen over the background color
textColors = repmat(confpercent(:) > midValue,1,3);
set(hStrings,{'Color'},num2cell(textColors,2));
% Setting the axis labels
set(gca,'XTick',1:numlabels,...
'XTickLabel',labels,...
'YTick',1:numlabels,...
'YTickLabel',labels,...
'TickLength',[0 0]);
If you have the neural network toolbox you can use the function plotconfusion. You can create a copy and edit it to customise it further, for example to print custom labels.
I have a MATLAB subplot figure. I need the YLabels to left align justify. To do this I am setting the Position property for each ylabel. My problem is the subplots are being created programmatically and therefore I don't know what to set the position as.
In MATLAB I want to use the longest/widest YTickLabel as a reference point for positioning. To do that I want to get the length of each label. I am able to get the YTickLabels by doing:
% Set Label format as string
set(gca, 'YTickLabel', num2str(transpose(get(gca, 'YTick'))))
% Get axis YTickLabels
ax = gca;
labels = get(ax, 'YTickLabel');
% Print labels to console
disp(labels)
I would like to iterate through the labels and find the length of the longest label. I've tried accessing them as a cell array but get 'Cell contents reference from a non-cell array object error.' And when I try matrix indexing nothing prints.
Does anyone know if it is possible to get the length of each individual YTickLabel value?
Useful info:
MATLAB R2014b
By "length of each individual YTickLabel value" I understand that you wish to get the number of characters forming each label.
It's quite easy using the numel function, which outputs the number of elements in a cell for an example. Since labels are stored in a cell array, we can use the fancy function cellfun to apply numel to each cell, then convert to a numeric array with cell2mat
In short you can use this:
LabelLength = cell2mat(cellfun(#(x) numel(x),labels,'uni',0))
here is some sample code to illustrate:
clear
clc
close all
x = 1:5;
y = rand(size(x));
scatter(x,y,40,'r','filled')
set(gca,'YTick',[1 3 5],'YTickLabel',{'One';'ThisIsThree';'AndFive'})
grid on
labels = get(gca,'YTickLabel')
LabelLength = cell2mat(cellfun(#(x) numel(x),labels,'uni',0))
and output:
LabelLength =
3
11
7
You could replace cellfun with this equivalent for-loop:
LabelLength = zeros(numel(labels),1);
for k = 1:numel(labels)
LabelLength(k) = numel(labels{k});
end
LabelLength
Note that as a workaround offering quite a lot of flexibility, you could replace the YTickLabels by text objects, for which you can set the HorizontalAlignment property to left for the text to be left-justified.
Hope that helps!
I am using the matlab to plot some project figures, see the blow figure. Now I am trying to cut the legend width so that the line won't look so wide. I tried these command as suggest by Benoit_11:
[~,icons,~,~] = legend(leg,'location','northwest');
hline = icons(2);
linedata = get(hline,'xdata');
newdata = [linedata(1)+0.2 linedata(2)];
set(hline,'xdata',newdata,'linewidth',1)
I am using the for loop to plot these figures because I have multiple figures to analysis at the same time. Now I can change the length of the legend line right now. But I got another problem: if I have different length of legend text, even if I set the same starting point and end point, I will get different length for the line in the end (you can see that from the figures). I tried to modify icon(1) but always got the error. Any suggestions?
There are 2 things you are not doing right with your code (aside the fact that you use size as the handles to the legend...that's risky because size is a built-in function):
1) Calling legend with only 1 argument returns a handle to the legend object and getting its position actually gives you the position of the box enclosing the legend, i.e. the text + the line.
2) Using this line:
p(3) = p(3) - 0.06;
does modify the position, however you would need to set the new position of the legend with something like the following for the changes to be effective:
set(HandleToLegend,'Position',p)
To come back to your question, the trick is to assign many outputs during the call to legend; you can then modify specific elements of the legend object.
Actually we only need 1 of the 4 output arguments, called icons in the docs so I'll stick with the notation. Then, we can get the XData property of the line and modify it as we want. The XData is actually a 2-element vector:
[StartingPoint EndingPoint]
so changing one or the other (or both) will change the length of the line displayed in the legend box.
Here is the whole code with comments; I changed the length and linewidth of the line in the 2nd plot to highlight the changes.
clear
clc
close all
x = 1:10;
y = rand(1,10);
figure;
%// Default case
subplot(1,2,1)
plot(x,y);
legend('First plot','Location','NorthWest');
title('Before','FontSize',18);
%// With modifications
subplot(1,2,2)
plot(x,y);
title('After','FontSize',18);
%//========================
%// Change the legend here
%//========================
%// The "icons" output is what you want
[~,icons,~,~] = legend('First plot','Location','NorthWest');
%// icons(1) is the text of the current element in the legend Here its 'First plot'
i_1 = get(icons(1)); %// access the properties with this command.
%// icons(2) is the line associated with that text. Here the blue line.
i_2 = get(icons(2));
%// Mhh I don't know what icons(3) represents haha sorry about that.
i_3 = get(icons(3));
%// Get the actual line
hline = icons(2);
%// Fetch its XData property
LineData = get(hline,'XData')
%// Play with those 2 elements to see the output change.
NewData = [LineData(1)+.2 LineData(2)-.01];
%// Apply the changes
set(hline,'XData',NewData,'LineWidth',3)
Which gives the following:
You need to set the value of the Position property, you can just change the vector p. p does not affect the plot at all, it's just a vector of numbers. You have to modify it, then apply it back to the plot, using
set(size,'Position',p)
There does seem to be a minimum width of the legend however.
I am wondering if it is possible to label the contours of a MATLAB contour plot with a set of user-defined strings?
I am currently using the following code snipper to produce a labelled contour plot:
%Create Data
X = 0.01:0.01:0.10
Y = 0.01:0.01:0.10
Z = repmat(X.^2,length(X),1) + repmat(Y.^2,length(Y),1)';
%Create Plot
hold on
[C,h] = contourf(X,Y,Z);
%Add + Format Labels to Plot
hcl = clabel(C,h,'FontSize',10,'Color','k','Rotation',0);
set(hcl,'BackgroundColor',[1 1 1],'EdgeColor',[0 0 0],'LineStyle','-',)
hold off
The issue with this code is that the labels are automatically generated by MATLAB. Even as I can easily change the contours that are labels, I cannot change the labels that they get.
Ideally, I would like to label them with a set of strings that I define myself. However if that is not possible, then I am wondering if it is possible to change the numeric format of the labels. The reason for this is that the code above actually produce a contour plot for an error rate, which I would like to display as a % value (i.e. use 1% in the contour label, instead of 0.01 etc.).
In this case, hcl is actually an array which stores handles to every contour label on your plot. When you set properties using the array (as in your code),
set(hcl, 'name', 'value')
You will set the property of every label to the same value.
You can change the properties of individual labels by iterating over the array. For example, this is how you would add a percentage sign:
for i = 1:length(hcl)
oldLabelText = get(hcl(i), 'String');
percentage = str2double(oldLabelText)*100;
newLabelText = [num2str(percentage) ' %'];
set(hcl(i), 'String', newLabelText);
end