Figure legend is being cut off MATLAB - matlab

I'm trying to plot 81 variables into one plot in MATLAB and I need a legend with 81 respective labels. I've managed to separate the legend into several lines such that it would fit the figure better but still, being this large, the legend apears cut off:
is there any way to solve this problem, so that all the legend appears in the figure?
Thank you in advance

In my experience, the legend is not manageable once the number of plots becomes so large.
You could try and hack this out by hand by trying to make a compact legend my manually moving the legend lines and text boxes around individually--but I fear this way will ultimately make you unhappy. If you want, you could start playing with the legend pieces by writing something like:
hl = legend(uniqueHandles, myNames);
hlc = get(hl, 'children');
This may not be possible and MATLAB will resist you. Instead, consider that a legend with 81 different colors becomes very hard to manage and you can't really tell the colors apart anyway. Instead of trying to get them all to fit I recommend grouping them into different colors and styles and then only showing 3-7 different sets like this:
This could be further improved by customizing the data tip so that when you click on a line it gives you more detail.
I put together some basic code to show how you might do this. It has some shortcomings. Regardless, in this example I plot everything at once then go back and group the colors together. I then pick out a representative line from each grouping and use it as an example in the legend. You could also plot everything, color it correctly, and then plot a new line in the existing axis with a value nan and use THOSE in the legend.
(edit) I also noted that you have grouped the colors already for some of them, so this should flow naturally from the work you've already done. If nothing else, you could grab the handles from every third entry and then only have 27 items in your legend... but best if you can reduce it further.
The example to create the above image is as follows:
%% Setup the problem:
nd = 81;
nx = 256;
data = zeros(nx,nd);
t = linspace(0, 2*pi, nx);
%% We divide the data into 3 groups and set a color for each. This calculation then notes what group each line belongs to:
myCategory = ceil((1:nd)/27);
myColor = myColors(myCategory)';
myColors = ['r', 'b', 'g'];
myNames = {'1 to 27', '28 to 54', '55 to 81'};
%% Make a simple set of data:
randn('seed', 1982);
dt = 0;
for ind = 1:nd
dt = dt+randn/5;
data(:, ind) = sin(t+dt) + dt*cos(t);
end
%% Plot all at once:
figure(33);
clf;
h = plot(data);
%% find the unique entries and choose one representative line for the legend.
%% We then use the handles of these lines to create the legend:
lastColor = -1;
uniqueHandles = [];
for ind = 1:nd
set(h(ind), 'color', myColor(ind));
if lastColor ~= myColor(ind)
lastColor = myColor(ind);
uniqueHandles(end+1) = h(ind);
end
end
% make the legend:
legend(uniqueHandles, myNames);

Related

Logarithmic x axis in a stackplot MatLab

I'm trying to make a stack plot from a table, to present several variables with the same x-axis. however, I want the x-axis to be logarithmic. I couldn't find any way in stackplot documentation. Does anyone have any suggestions on how I can solve this?
I have tried using subplots instead, however, that way my graphs would not fit all on one page and I would have a lot of white space between the subplots. Therefore, I chose stackplot to make it more nice and less space-consuming.
tbl = readtable('usage.csv');
newYlabels = {'Heating (kWh/year)','Cooling (kWh/year)','Electricity (kWh/year)'};
stackedplot(tbl,[{2:16},{17:27},{28:35}],'XVariable',[1],'DisplayLabels',newYlabels);
Here is the output of the code:
Here is an image of what I'm trying to make, but the x-axis needs to be the real variable (\beta) in logarithmic scale
stackedplot has unfortunately no logarithmic axes option, and since it creates a StackedAxes instead of a normal Axes object, there is no way to changes this.
If the only reason you want to use stackedplot is to have less white-space, you might want to check out tight_subplot on the Matlab FEX. This would allow you to just do: set(ax, 'XScale', 'log').
You can however take the log of your x-data, and add that to the table:
tbl = readtable('outages.csv'); % sample data
tbl = sortrows(tbl, 'OutageTime'); % sort by date
% make x vector; for example just row numbers
x = (1:size(tbl,1)).';
xlog = log10(x);
% add x to table
tbl.Xlog = xlog;
tbl.X = x;
% plot normal x
f = figure(1); clf;
s = stackedplot(tbl, {'Loss'}, 'XVariable', 'X');
xlabel('rows');
% plot log(x)
f = figure(2); clf;
s = stackedplot(tbl, {'Loss'}, 'XVariable', 'Xlog');
xlabel('log(rows)')
Normal:
Log:

How to make all the legend appear in a plot?

Im using this code to plot X vector vs all the columns of the table on example.txt
C = readtable('example.txt', 'Delimiter',',');
X = 5:5:430;
%%
for i=1:numel(X)
plot(X,C{:,i})
hold on
grid on
end
LegendString = cell(1,numel(X));
hold all
for k = 1:numel(X)
LegendString{k} = sprintf('%i',X(k));
end
legend(LegendString)
Here you can download the example.txt file to run the code:
https://la.mathworks.com/matlabcentral/answers/383371-how-to-make-all-the-legend-appear-in-a-plot
Why the plot is only showing me 50 legends and not all the 86 the code is asking?
It's not a Matlab bug, but an intentional behavior: legends are currently limited to 50 elements (you may have noticed that your plot legend contains 50 items in fact, instead of 86). This limit has probably been introduced in order to avoid the creation of excessively big legends, which:
are hard to read (especially if they overflow the plot window);
are computationally expensive to draw;
occupy a huge volume of memory.
Traces of this hardcoded limit can be found in the legend script itself (in order to view it, run open legend in the Command Window). For legends created with explicit labels passed as argument, the limit is probably applied internally somewhere in the class that handles the graphic components of the legend. For legends created without a defined set of labels, the subfunction set_children_and_strings applies this limit:
if auto_children && length(ch) > 50,
% only automatically add first 50 to cut down on huge lists
ch = ch(1:50);
end
matlab.graphics.illustration.internal.generateDisplayNames(ch);
In order to overcome this limit, you have two alternatives:
select just a few elements to display in the legend;
use a workaround by creating one legend for each group of 50 items.
EDIT
C = readtable('data.txt','Delimiter',',');
X = 5:5:430;
X_len = numel(X);
X_seq = 1:numel(X);
figure();
hold on;
grid on;
h = gobjects(X_len,1);
for i = X_seq
h(i) = plot(X,C{:,i});
end
legend(h(2:2:X_len),sprintfc('%d',10:10:430));

How to display statistics as text in a graph?

I am using cdfplot in matlab to plot the empirical CDF of certain quantities.
[h,stats]=cdfplot(quantity)
Now stats returns me a structure having min, max, mean etc. I want these values to be displayed as text in the graph.
I have lot of similar graphs to plot and do not want to do it manually.
To put a text on a plot you use the text function. Here is a quick example on one plot:
y = evrnd(0,3,100,1);
[h, stats] = cdfplot(y);
hold on
x = -20:0.1:10;
f = evcdf(x,0,3);
plot(x,f,'m')
legend('Empirical','Theoretical','Location','NW')
stat_type = {'min: ';'max: ';'mean: ';'median: ';'std: '}; % make titles
stat_val = num2str(struct2array(stats).'); % convert stats to string
text(-15,0.7,stat_type) % <-- here
text(-11,0.7,stat_val) % <-- and here
hold off
This will give:
and you can use it inside a loop to do it for all the graphs.
The tricky thing is to define where to put the text on the graph. Here I choose (-15,0.7) and (-11,0.7) as a fixed points where I know there is no data. You should look at your plots, and find the correct place for that.

Plot a cell into a time-changing curve

I have got a cell, which is like this : Data={[2,3],[5,6],[1,4],[6,7]...}
The number in every square brackets represent x and y of a point respectively. There will be a new coordinate into the cell in every loop of my algorithm.
I want to plot these points into a time-changing curve, which will tell me the trajectory of the point.
As a beginner of MATLAB, I have no idea of this stage. Thanks for your help.
Here is some sample code to get you started. It uses some basic Matlab functionalities that you will hopefully find useful as you continue using it. I added come data points to you cell array for illustrative purposes.
The syntax to access elements into the cell array might seem weird but is important. Look here for details about cell array indexing.
In order to give nice colors to the points, I generated an array based on the jet colormap built-in in Matlab. Basically issuing the command
Colors = jet(N)
create a N x 3 matrix in which every row is a 3-element color ranging from blue to red. That way you can see which points were detected before other (i.e. blue before red). Of course you can change that to anything you want (look here if you're interested).
So here is the code. If something is unclear please ask for clarifications.
clear
clc
%// Get data
Data = {[2,3],[5,6],[1,4],[6,7],[8,1],[5,2],[7,7]};
%// Set up a matrix to color the points. Here I used a jet colormap
%// available from MATLAB but that could be anything.
Colors = jet(numel(Data));
figure;
%// Use "hold all" to prevent the content of the figure to be overwritten
%// at every iterations.
hold all
for k = 1:numel(Data)
%// Note the syntax used to access the content of the cell array.
scatter(Data{k}(1),Data{k}(2),60,Colors(k,:),'filled');
%// Trace a line to link consecutive points
if k > 1
line([Data{k-1}(1) Data{k}(1)],[Data{k-1}(2) Data{k}(2)],'LineStyle','--','Color','k');
end
end
%// Set up axis limits
axis([0 10 0 11])
%// Add labels to axis and add a title.
xlabel('X coordinates','FontSize',16)
ylabel('Y coordinates','FontSize',16)
title('This is a very boring title','FontSize',18)
Which outputs the following:
This would be easier to achieve if all of your data was stored in a n by 2 (or 2 by n) matrix. In this case, each row would be a new entry. For example:
Data=[2,3;
5,6;
1,4;
6,7];
plot(Data(:, 1), Data(:, 2))
Would plot your points. Fortunately, Matlab is able to handle matrices which grow on every iteration, though it is not recommended.
If you really wanted to work with cells, there are a couple of ways you could do it. Firstly, you could assign the elements to a matrix and repeat the above method:
NumPoints = numel(Data);
DataMat = zeros(NumPoints, 2);
for I = 1:NumPoints % Data is a cell here
DataMat(I, :) = cell2mat(Data(I));
end
You could alternatively plot the elements straight from the cell, though this would limit your plot options.
NumPoints = numel(Data);
hold on
for I = 1:NumPoints
point = cell2mat(Data(I));
plot(point(1), point(2))
end
hold off
With regards to your time changing curve, if you find that Matlab starts to slow down after it stores lots of points, it is possible to limit your viewing window in time with clever indexing. For example:
index = 1;
SamplingRate = 10; % How many times per second are we taking a sample (Hertz)?
WindowTime = 10; % How far into the past do we want to store points (seconds)?
NumPoints = SamplingRate * WindowTime
Data = zeros(NumPoints, 2);
while running
% Your code goes here
Data(index, :) = NewData;
index = index + 1;
index = mod(index-1, NumPoints)+1;
plot(Data(:, 1), Data(:, 2))
drawnow
end
Will store your data in a Matrix of fixed size, meaning Matlab won't slow down.

Matlab plot of several digital signals

I'm trying to find a way to nicely plot my measurement data of digital signals.
So I have my data available as csv and mat file, exported from an Agilent Oscilloscope. The reason I'm not just taking a screen shot of the Oscilloscope screen is that I need to be more flexible (make several plots with one set of data, only showing some of the lines). Also I need to be able to change the plot in a month or two so my only option is creating a plot from the data with a computer.
What I'm trying to achieve is something similar to this picture:
The only thing missing on that pic is a yaxis with 0 and 1 lines.
My first try was to make a similar plot with Matlab. Here's what I got:
What's definitely missing is that the signal names are right next to the actual line and also 0 and 1 ticks on the y-axis.
I'm not even sure if Matlab is the right tool for this and I hope you guys can give me some hints/a solution on how to make my plots :-)
Here's my Matlab code:
clear;
close all;
clc;
MD.RAW = load('Daten/UVLOT1 debounced 0.mat'); % get MeasurementData
MD.N(1) = {'INIT\_DONE'};
MD.N(2) = {'CONF\_DONE'};
MD.N(3) = {'NSDN'};
MD.N(4) = {'NRST'};
MD.N(5) = {'1V2GD'};
MD.N(6) = {'2V5GD'};
MD.N(7) = {'3V3GD'};
MD.N(8) = {'5VGD'};
MD.N(9) = {'NERR'};
MD.N(10) = {'PGD'};
MD.N(11) = {'FGD'};
MD.N(12) = {'IGAGD'};
MD.N(13) = {'GT1'};
MD.N(14) = {'NERRA'};
MD.N(15) = {'GT1D'};
MD.N(16) = {'GB1D'};
% concat vectors into one matrix
MD.D = [MD.RAW.Trace_D0, MD.RAW.Trace_D1(:,2), MD.RAW.Trace_D2(:,2), MD.RAW.Trace_D3(:,2), ...
MD.RAW.Trace_D4(:,2), MD.RAW.Trace_D5(:,2), MD.RAW.Trace_D6(:,2), MD.RAW.Trace_D7(:,2), ...
MD.RAW.Trace_D8(:,2), MD.RAW.Trace_D9(:,2), MD.RAW.Trace_D10(:,2), MD.RAW.Trace_D11(:,2), ...
MD.RAW.Trace_D12(:,2), MD.RAW.Trace_D13(:,2), MD.RAW.Trace_D14(:,2), MD.RAW.Trace_D15(:,2)];
cm = hsv(size(MD.D,2)); % make colormap for plot
figure;
hold on;
% change timebase to ns
MD.D(:,1) = MD.D(:,1) * 1e9;
% plot lines
for i=2:1:size(MD.D,2)
plot(MD.D(:,1), MD.D(:,i)+(i-2)*1.5, 'color', cm(i-1,:));
end
hold off;
legend(MD.N, 'Location', 'EastOutside');
xlabel('Zeit [ns]'); % x axis label
title('Messwerte'); % title
set(gca, 'ytick', []); % hide y axis
Thank you guys for your help!
Dan
EDIT:
Here's a pic what I basically want. I added the signal names via text now the only thing that's missing are the 0, 1 ticks. They are correct for the init done signal. Now I just need them repeated instead of the other numbers on the y axis (sorry, kinda hard to explain :-)
So as written in my comment to the question. For appending Names to each signal I would recommend searching the documentation of how to append text to graph. There you get many different ways how to do it. You can change the position (above, below) and the exact point of data. As an example you could use:
text(x_data, y_data, Var_Name,'VerticalAlignment','top');
Here (x_data, y_data) is the data point where you want to append the text and Var_Name is the name you want to append.
For the second question of how to get a y-data which contains 0 and 1 values for each signal. I would do it by creating your signal the way, that your first signal has values of 0 and 1. The next signal is drawn about 2 higher. Thus it changes from 2 to 3 and so on. That way when you turn on y-axis (grid on) you get values at each integer (obviously you can change that to other values if you prefer less distance between 2 signals). Then you can relabel the y-axis using the documentation of axes (check the last part, because the documentation is quite long) and the set() function:
set(gca, 'YTick',0:1:last_entry, 'YTickLabel',new_y_label(0:1:last_entry))
Here last_entry is 2*No_Signals-1 and new_y_label is an array which is constructed of 0,1,0,1,0,....
For viewing y axis, you can turn the grid('on') option. However, you cannot chage the way the legends appear unless you resize it in the matlab figure. If you really want you can insert separate textboxes below each of the signal plots by using the insert ->Textbox option and then change the property (linestyle) of the textbox to none to get the exact same plot as above.
This is the end result and all my code, in case anybody else wants to use the good old ctrl-v ;-)
Code:
clear;
close all;
clc;
MD.RAW = load('Daten/UVLOT1 debounced 0.mat'); % get MeasurementData
MD.N(1) = {'INIT\_DONE'};
MD.N(2) = {'CONF\_DONE'};
MD.N(3) = {'NSDN'};
MD.N(4) = {'NRST'};
MD.N(5) = {'1V2GD'};
MD.N(6) = {'2V5GD'};
MD.N(7) = {'3V3GD'};
MD.N(8) = {'5VGD'};
MD.N(9) = {'NERR'};
MD.N(10) = {'PGD'};
MD.N(11) = {'FGD'};
MD.N(12) = {'IGAGD'};
MD.N(13) = {'GT1'};
MD.N(14) = {'NERRA'};
MD.N(15) = {'GT1D'};
MD.N(16) = {'GB1D'};
% concat vectors into one matrix
MD.D = [MD.RAW.Trace_D0, MD.RAW.Trace_D1(:,2), MD.RAW.Trace_D2(:,2), MD.RAW.Trace_D3(:,2), ...
MD.RAW.Trace_D4(:,2), MD.RAW.Trace_D5(:,2), MD.RAW.Trace_D6(:,2), MD.RAW.Trace_D7(:,2), ...
MD.RAW.Trace_D8(:,2), MD.RAW.Trace_D9(:,2), MD.RAW.Trace_D10(:,2), MD.RAW.Trace_D11(:,2), ...
MD.RAW.Trace_D12(:,2), MD.RAW.Trace_D13(:,2), MD.RAW.Trace_D14(:,2), MD.RAW.Trace_D15(:,2)];
cm = hsv(size(MD.D,2)); % make colormap for plot
figure;
hold on;
% change timebase to ns
MD.D(:,1) = MD.D(:,1) * 1e9;
% plot lines
for i=2:1:size(MD.D,2)
plot(MD.D(:,1), MD.D(:,i)+(i-2)*2, 'color', cm(i-1,:));
text(MD.D(2,1), (i-2)*2+.5, MD.N(i-1));
end
hold off;
%legend(MD.N, 'Location', 'EastOutside');
xlabel('Zeit [ns]'); % x axis label
title('Messwerte'); % title
% make y axis and grid the way I want it
set(gca, 'ytick', 0:size(MD.D,2)*2-3);
grid off;
set(gca,'ygrid','on');
set(gca, 'YTickLabel', {'0'; '1'});
ylim([-1,(size(MD.D,2)-1)*2]);