I am trying to create a bar chart where my x axis shows only one data point, year of 2006, but for 3 different data related to 2006. I am doing the following, but I receive the
error of "X must be same length as Y."
Here is my code and I highly appreciate your help:
X=[2006] %year
% Create data for childhood disease cases
measles = [38556];
mumps = [20178];
chickenPox = [37140];
% Create a vertical bar chart using the bar function
figure;
bar(X, [measles' mumps' chickenPox'],'group');
% Set the axis limits
%axis([0 13 0 40000]);
% Add title and axis labels
title('Childhood diseases by month');
xlabel('Month');
ylabel('Cases (in thousands)');
% Add a legend
legend('Measles', 'Mumps', 'Chicken pox');
You are getting this error because X is only one element and you are using three different Y values.
I think this problem requires you to take a step back a bit. Why are you plotting all three against the same X value? If this worked as you specified, all three would be on top of each other.
Would it not be more informative to the viewer if the X-axis labeled each bar as measles, mumps or chickenPox?
Try:
bar([measles' mumps' chickenPox']);
set(gca,'XTickLabel',{'Measles','Mumps','Chicken Pox'});
Edit:
I see what you're after. You're almost correct. The problem is that since you only have one column of data, matlab assumes you DON'T want to create a group but just plot those 3 values against unique X values. So we need to trick it slightly by creating another data point.
% //Create two columns, one of them zeros
data = [[measles;mumps;chickenPox],[0;0;0]];
bar([X,X+1],data'); % //The 2007 entry will not be visible
This will create a group at 2006 and the 2007 entry will be zeros so you won't see it. You can then set your axes and such to be the same as the other charts.
Related
Is it possible to make multiple vertical histograms plot in Matlab into one? Much like the excel sheet enclosed ( https://drive.google.com/file/d/1H_mbyrIoln3XrnK1hLajnVNBKn13y_np/view?usp=sharing )
I want to make a plot of many vertical histogram plots into one figure, by importing excel-files, where on the y axis it has the elevation, the x axis the distance between the histogram vertical lines and the length of the histogram bars is the values in the excel sheet. The vertical height of each bar is 5.
Is this even possible? I have to put in a number of conditions for Matlab to know where to plot, but could some one show me the basic methodology?
Help would be very much appreciated!
The problem is that the parent of a Baseline object is the Axis, which prevents us from doing something like
barh(bins1,counts1,'Basevalue',baseline1); hold on;
barh(bins2,counts2,'Basevalue',baseline2); hold off;
because the plots will automatically share the second baseline value set. There might be a workaround for this that I do not know of, so I invite anybody who knows it to show me how its done.
For now, I was able to sort-of replicate the plot you posted a picture of in a much less elegant way. I will post code below, but before I do, I would like to argue against the use of a plot like this. Why? Because I think it is confusing, as the x-axis both relates to the plot number as well as the bin count numbers. You are in fact trying to display a 3-D data set, the three dimensions being bins, bin counts, and 'histogram number'. A plethora of methods exist for displaying 3-D data, and a series of 2-D histograms may not be the best way to go.
That being said, here is a code that more-or-less creates the picture above, as promised. Any changes you may want to make will be more cumbersome than usual :-)
testData = randn(10000,1); % Generate some data
[counts,bins] = hist(testData); % Bin the data
% First histogram
baseline1 = 0;
p1=subplot(1,3,1); barh(bins,counts,'BaseValue',baseline1);
xticks(baseline1); xticklabels({0}); % Graph number on x axis at baseline (0)
box off; % Remove box on right side of plot
ylabel('Property');
% Second histogram
baseline2 = max(counts)*1.2;
sepdist = baseline2-baseline1; % Distance that separates two baselines
counts2 = baseline2 + counts;
p2=subplot(1,3,2); barh(bins,counts2,'BaseValue',baseline2)
xticks(baseline2); xticklabels({1}); % Graph number on x axis at baseline
box off;
Y=gca; Y.YAxis.Visible='off';
p1p=p1.Position; p2p=p2.Position;
p2p(1)=p1p(1)+p1p(3); p2.Position=p2p; % Move subplot so they touch
% Third histogram
baseline3 = baseline2 + sepdist;
counts3 = baseline3+counts;
p3=subplot(1,3,3); barh(bins,counts3,'BaseValue',baseline3)
xticks(baseline3); xticklabels({2});
Y=gca; Y.YAxis.Visible='off';
box off
p3p=p3.Position;
p3p(1)=p2p(1)+p2p(3); p3.Position=p3p;
% Add x-label when you are done:
xl=xlabel('Test xlabel'); xl.Units='normalized';
% Fiddle around with xl.Position(1) until you find a good centering:
xl.Position(1) = -0.49;
Result:
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 am trying to plot some data with Matlab R2015a and as the data sets are changing for different plots I want to create the legend (semi-)automatically. I do this with a list of strings (called list) and then
leg = legend(list);
legtxt=findobj(leg,'type','text');
set(legtxt(1),'color','r');
set(legtxt(2),'color','b');
a.s.o. according to the entries.
However, no matter what index I give in the 'set(legtxt(i))' part, Matlab always tells me 'Index exceeds matrix dimensions.' Same, if I create the the legend manually by not using 'legend(list)' but explicitly typing the legend entries. Does anyone know why this happens or how to solve it? Thanks!
You need to use additional outputs from the call to legend. Specifically, check out the 2nd output called icons in the docs.
As for the error, the call to findobj(...) yields an empty vector, so matrix dimensions are indeed exceeded. Indeed (from the docs):
Starting in R2014b, the legend function returns a legend object. In
previous releases it returns an axes object.
So maybe that's why you can't use findobj to fetch legend text...
Anyhow here is how to solve your problem. In this example I create 3 plots and change the color of the text of the 1st and 2nd entry inside the legend:
x = 1:10;
y1 = sin(x);
y2 = cos(x);
y3 = x;
plot(x,y1,'y*',x,y2,'g--',x,y3,'k')
list = {'y1';'y2';'y3'};
%// You want to play with icons and possibly plots.
[leg,icons,plots,str] = legend(list)
set(icons(1),'color','r','FontSize',12)
set(icons(2),'color','b','FontSize',12)
Output:
Of course you can use the plots output to change any property you want of the plots to make them fit with their legend entry.
Quick version
How can I control the x- and y-values for a 3-d bar plot in Matlab?
Details
Say we have an 10 x 20 data matrix and we plot it using bar3, and we want to set the x- and y-values. For instance:
foodat = rand(10,20);
xVals = [5:14];
yVals = [-3:16];
bar3(xVals, foodat);
xlabel('x'); ylabel('y');
Is there a way to feed it the yVals as well? Otherwise the y axes always defaults to [1:N].
Note I don't just want to change the labels using XTickLabel and YTickLabel. I need to change the actual values on the axes, because I am plotting multiple things in the same figure. It isn't enough to just change how the (wrong) axis ticks are labeled. So this is different from issues like this:
How can I adjust 3-D bar grouping and y-axis labeling in MATLAB?
Other things I have tried
When I try changing the xvals with:
set(gca,'XTick', xVals)
set(gca,'YTick', yVals)
The values are taken in, but actually show up on the wrong axes, so it seems x and y axes are switched using bar3. Plus, it is too late anyway as the bar graph was already plotted with the wrong x- and y-values, so we would end up giving ticks to empty values.
Note added
Matlab tech support just emailed me to let me know about the user contributed function scatterbar3, which does what I want, in a different way than the accepted answer:
http://www.mathworks.com/matlabcentral/fileexchange/1420-scatterbar3
I found a way of doing it. Ill give you a piece of code, then you'll need to "tidy up" , mainly the axis limits and the Xticks, as bar3 does set up the Xticks inside, so if you want others you'll need to set them manually yourself.
So the trick here is to get the Xdata from the bar3 handle. The thing here is that it seems that there is a handle for each row of the data, so you need to iterate for each of them. Here is the code with the current output:
foodat = rand(20,10);
xVals = [5:14];
yVals = [-3:16];
% The values of Y are OK if called like this.
subplot(121)
bar3(yVals, foodat);
subplot(122)
h=bar3(yVals, foodat);
Xdat=get(h,'XData');
axis tight
% Widdth of barplots is 0.8
for ii=1:length(Xdat)
Xdat{ii}=Xdat{ii}+(min(xVals(:))-1)*ones(size(Xdat{ii}));
set(h(ii),'XData',Xdat{ii});
end
axis([(min(xVals(:))-0.5) (max(xVals(:))+0.5) min(yVals(:))-0.5, max(yVals(:))+0.5])
Note: Y looks different but is not.
As you can see now the X values are the ones you wanted. If you'd want other size than 1 for the intervals between them you'd need to change the code, but you can guess how probably!
I need to make a bar graph in matlab with 3 bars. The values for the three bars is stored in x. Now I want a to make a legend: Each bar should be labeled with a letter e.g. 'A','B','C'.
x = rand(1,3); bar(x); legend('A','B','C');
Did not work.
Then I tried this example: http://www.mathworks.com/matlabcentral/fileexchange/35271-matlab-plot-gallery-vertical-bar-plot/content/html/Vertical_Bar_Plot.html
But as soon as you reduce the the number of entries in each category to 1, you'll get an error message, but I think the message is wrong =/ it works with any number but just not with 1...
So is there a simple solution to that problem?
What you want is a "three series plot" - unfortunately, as soon as you make it 1x3, Matlab thinks it's just a single series. We have to trick it into thinking you have three series. Here's how you do that:
x = rand(1,3);
x2 = [x; x*0]; % add a second row of all zeros
figure
bar(x2); % now we have a plot with an ugly second category
xlim([0.5 1.5]); % trick that hides second category
legend('a','b','c'); % add the legend
set(gca, 'XTickLabel', ''); % hide the '1' on the X axis (or make it whatever you want)
title 'Bar plot with legend - demo'
Result is then something like this:
I believe this is exactly what you were asking for.