Add error bars to grouped bar plot in MatLab - matlab

I have a simple, grouped bar plot. I'm trying to plot the error bars, too, but I can't seem to figure it out.
I'm not too great with for loops, but I don't know if that's the only solution to this, or if I can just add another line of code to plot the error bars.
Here's my code and graph:
% Plot raw data
y = [316.45 292.14 319.96; 305.59 287.99 295.21] % first 3 #s are pre-test, second 3 #s are post-test
err = [13.12 5.67 12.36; 12.43 6.83 11.67]
box on
bar(y)
set(gca,'xticklabel',{'Pre-test'; 'Post-test'})
ylim([200 360])
ylabel('RT (ms)')
xlabel('Session')

Here is a solution using the standard errorbar and bar functions. bar plots each group at the same x position, and uses the Xoffset property to shift the bars in a group. You can use the x position and Xoffset to plot the errorbars.
% Data
y = [316.45 292.14 319.96; 305.59 287.99 295.21] % first 3 #s are pre-test, second 3 #s are post-test
err = [13.12 5.67 12.36; 12.43 6.83 11.67]
% Plot
figure(1); clf;
hb = bar(y); % get the bar handles
hold on;
for k = 1:size(y,2)
% get x positions per group
xpos = hb(k).XData + hb(k).XOffset;
% draw errorbar
errorbar(xpos, y(:,k), err(:,k), 'LineStyle', 'none', ...
'Color', 'k', 'LineWidth', 1);
end
% Set Axis properties
set(gca,'xticklabel',{'Pre-test'; 'Post-test'});
ylim([200 360])
ylabel('RT (ms)')
xlabel('Session')

Related

How to position bars along side the X axis in bar3?

I am trying to plot bars using bar3 on a background image. Although the bar3 command is able to move the bars alongside the Y-axis, I have no idea how to move the bars in the X-axis direction.
This is an example of what I use, but still cannot move the bars in the X-axis.
A = [10 5 20 8];
bar3(1:4, A)
xlabel('x'); ylabel('y');
Do you have any ideas how to move the bars to the desired position? Thanks!
You can modify the X coordinate of your bars after they have been created and move them where ever you want them. The example below moves the 4 bars in your example, output img shown below.
f = figure;
ax = axes ( 'parent', f );
A = [10 5 20 8];
h = bar3(ax, 1:4, A );
xlabel('x');
ylabel('y');
% create some new positions for the xdata
index = randperm(4);
% the xdata is blocks on 6x4 coordinates
start = 1;
for ii=1:4
finish = start+5;
% for each block of data update the x co-ordinate
% this will "move" if along the x-axis
h.XData(start:finish,:)=h.XData(start:finish,:)+index(ii);
start = finish+1;
end
% Update the xlim of the axes to display them
ax.XLim = [0 5];

Using roof of a graph as x-axis for another

I've plotted a graph using pcolor which gives me the following graph-
My aim is to use the roof of the graph (by roof) I mean the highest axis (in this case, the line which is defined by y=57) as the base for a further graph.
I was able to use hold on to generate the following-
Code for this (removed some parts that defined the axis labels etc for brevity)-
load sparsemap ;
load d ;
residues = 57 ;
z = zeros(residues,residues); % define the matrix
index = find(sparsemap(:,3) ~= 0) ;
values = length(index);
hold on
%Plots the map you see in the first photo-
for k = 1:values
z(sparsemap(index(k),1),sparsemap(index(k),2)) = sparsemap(index(k),3);
z(sparsemap(index(k),2),sparsemap(index(k),1)) = sparsemap(index(k),3);
end
%Plots the line plot at the bottom of the graph.
A = d(:,1);
B = d(:,2) ;
plot(A, B) ;
pcolor(1:residues,1:residues,z);
works = load('colormap_works');
colormap(works);
colorbar;
As you can see, the line plot is using the same x axis as the first graph.
I am trying to get the line plot to come on top of the figure. I imagine a final figure like so-
Any ideas as to how I can use the top part of the first graph?
You can use 2 subplots. Here is an example:
data = randi(50,20,20); % some data for the pcolor
y = mean(data); % some data for the top plot
subplot(5,1,2:5) % create a subplot on the lower 4/5 part for the figure
pcolor(data) % plot the data
colormap hot;
h = colorbar('east'); % place the colorbar on the right
h.Position(1) = 0.94; % 'push' the colorbar a little more to the right
ax = gca;
pax = ax.Position; % get the position for further thightning of the axes
ax.YTick(end) = []; % delete the highest y-axis tick so it won't interfere
% with the first tick of the top plot
subplot(5,1,1) % create a subplot on the upper 1/5 part for the figure
plot(1:20,y) % plot the top data
ylim([0 max(y)]) % compact the y-axis a little
ax = gca;
ax.XAxis.Visible = 'off'; % delete the x-axis from the top plot
ax.Position(2) = pax(2)+pax(4); % remove the space between the subplots
Which creates this:

Add non-existent entry to legend

I want to add an entry manually to a MATLAB legend. This legend can be pre-existent and contain other graphed elements' entries, but not necessarily.
I make a scatter plot, but instead of using e.g. scatter(x,y), I plot it using
for n = 1:numel(x)
text(x(n),y(n),num2str(n), ...
'HorizontalAlignment','center','color',[1 0 0])
end
This results in a scatter plot of numbers one through the number of elements in x (and y, because they are of the same size). I want to add a legend entry for these numbers.
I tried to add or edit the legend with
[h,icons,plots,s] = legend(___)
as described on the legend documentation page. I can't figure out how I can add a legend entry, without having to plot something (such as an actual scatter plot or regular plot). I want the usual line or marker symbol in the legend to be a number or character such as 'n', indicating the numbers in the graph. Is this possible and how would one achieve this?
EDIT by Erik
My answer goes below zelanix's answer, because mine is based on it.
Original answer
A fairly workable solution may be as follows:
x = rand(10, 1);
y = rand(10, 1);
figure;
text(x,y,num2str(transpose(1:numel(x))),'HorizontalAlignment','center')
% Create dummy legend entries, with white symbols.
hold on;
plot(0, 0, 'o', 'color', [1 1 1], 'visible', 'off');
plot(0, 0, 'o', 'color', [1 1 1], 'visible', 'off');
hold off;
% Create legend with placeholder entries.
[h_leg, icons] = legend('foo', 'bar');
% Create new (invisible) axes on top of the legend so that we can draw
% text on top.
ax2 = axes('position', get(h_leg, 'position'));
set(ax2, 'Color', 'none', 'Box', 'off')
set(ax2, 'xtick', [], 'ytick', []);
% Draw the numbers on the legend, positioned as per the original markers.
text(get(icons(4), 'XData'), get(icons(4), 'YData'), '1', 'HorizontalAlignment', 'center')
text(get(icons(6), 'XData'), get(icons(6), 'YData'), '2', 'HorizontalAlignment', 'center')
axes(ax1);
Output:
The trick to this is that the new axes are created in exactly the same place as the legend, and the coordinates of the elements of the icons are in normalised coordinates which can now be used inside the new axes directly. Of course you are now free to use whatever font size / colour / whatever you need.
The disadvantage is that this should only be called after your legend has been populated and positioned. Moving the legend, or adding entries will not update the custom markers.
Erik's answer
Based on zelanix's answer above. It is a work-in-progress answer, I am trying to make a quite flexible function of this. Currently, it's just a script that you'd need to adapt to your situation.
% plot some lines and some text numbers
f = figure;
plot([0 1],[0 1],[0 1],[1 0])
x = rand(25,1);
y = rand(25,1);
for n = 1:numel(x)
text(x(n),y(n),num2str(n), ...
'HorizontalAlignment','center','color',[1 0 0])
end
hold on
% scatter(x,y) % used to test the number positions
scatter(x,y,'Visible','off') % moves the legend location to best position
% create the dummy legend using some dummy plots
plot(0,0,'o','Visible','off')
[l,i] = legend('some line','some other line','some numbers','location','best');
l.Visible = 'off';
% create empty axes to mimick legend
oa = gca; % the original current axes handle
a = axes;
axis manual
a.Box = 'on';
a.XTick = [];
a.YTick = [];
% copy the legend's properties and contents to the new axes
a.Units = l.Units; % just in case
a.Position = l.Position;
i = copyobj(i,a);
% replace the marker with a red 'n'
s = findobj(i,'string','some numbers');
% m = findobj(i(i~=s),'-property','YData','marker','o');
m = findobj(i(i~=s),'-property','YData');
sy = s.Position(2);
if numel(m)>1
dy = abs(m(1).YData - sy);
for k = 2:numel(m)
h = m(k);
dy2 = abs(h.YData - sy);
if dy2<dy
kbest = k;
dy = dy2;
end
end
m = m(kbest);
end
m.Visible = 'off';
mx = m.XData;
text(mx,sy,'n','HorizontalAlignment','center','color',[1 0 0])
% reset current axes to main axes
f.CurrentAxes = oa;
The result:

Zoom region within a plot in Matlab

I'm using Matlab to produce figures, and I'm wondering if there is a way to plot a zoomed region in a figure of the overall data?
I have scatter data plotted over one week, with the x-axis in hours, and I want to zoom into the first 3 hours, and display them within the main figure with the x-axis label of minutes.
The plotting code I have so far is as follows:
allvalsx = marabint(:,2)
allvalsy = marabint(:,5)
subvalsx = marabint(1:7,2);
subvalsy = marabint(1:7,2);
%% Plots the scatter chart.
sizemarker = 135
handle = scatter(allvalsx, allvalsy, sizemarker, '.')
figure(1)
axes('Position',[.2 .2 .2 .2])
handle2 = scatter(subvalsx, subvalsy, '.r')
title(plotTitle)
xlabel('Time since treatment (hours)')
ylabel('Contact angle (deg)')
% Axis scales x1, x2, y1, y2
axis([0, marabint(length(marabint),2) + 10, 0, 120]);
% This adds a red horizontal line indicating the untreated angle of the
% sample.
untreatedLine = line('XData', [0 marabint(length(marabint),2) + 10], 'YData', [untreatedAngle untreatedAngle], 'LineStyle', '-', ...
'LineWidth', 1, 'Color','r');
% Adding a legend to the graph
legendInfo = horzcat('Untreated angle of ', untreatedString)
hleg1 = legend(untreatedLine, legendInfo);
% This encases the plot in a box
a = gca;
% set box property to off and remove background color
set(a,'box','off','color','none')
% create new, empty axes with box but without ticks
b = axes('Position',get(a,'Position'),'box','on','xtick',[],'ytick',[]);
% set original axes as active
axes(a)
% link axes in case of zooming
linkaxes([a b])
set(gcf,'PaperUnits','inches');
set(gcf,'PaperSize', [8.267 5.25]);
set(gcf,'PaperPosition',[0 0.2625 8.267 4.75]);
set(gcf,'PaperPositionMode','Manual');
set(handle,'Marker','.');
print(gcf, '-dpdf', '-r150', horzcat('markertest4.pdf'));
This produces the following
Can anyone help me out with this?
yeah, I think I know what you need. Try this:
zoomStart = 0;
zoomStop = 3;
set(gca, 'XLim', [zoomStart zoomStop])
Let me know if that doesn't do what you need, and I'll give you a different way.

matlab bar colormap returns the same color for all bars

I have a problem with using bar and colormap.
I have a csv file like this which contains completion time for six tasks:
34,22,103,22,171,26
24,20,41,28,78,28
37,19,60,23,141,24
...
and I create a bar chart with of the means, and add the std variation errorbar.
res = csvread('sorting_results.csv');
figure();
y = mean(res)';
e = std(res);
hold on;
bar(y);
errorbar(y,e,'.r');
title('Sorting completion time');
ylabel('Completion time (seconds)');
xlabel('Task No.');
hold off;
colormap(summer(size(y,2)));
Why is the output like this? Why do the bars have the same color? And how do I put legends to the six bars?
A piece of code that does the magic. It doesn't use the canonical technique mentioned by #am304, as you will have a hard time setting up the legend with it. Here, for each one of the 6 input values, we plot a full 6 bars: one bar with the value and the remaining five set to zero.
x = rand(1,6); %create data
x_diag = diag(x); %zero matrix with diagonal filled with x
cmap = summer(6); %define colors to use (summer colomap)
figure('color','w','Render','Zbuffer'); %create figure
%bar plot for each x value
for ind_data = 1:length(x)
h_bar = bar( x_diag(ind_data, :)); %bar plot
set( get(h_bar,'children'), 'FaceVertexCData', cmap(ind_data,:) ) ; %color
hold on;
end
colormap('summer');
%legend-type info
hleg = legend( ('a':'f')' );
set(hleg, 'box', 'off');
%xticks info
set(gca, 'XTickLabel', ('a':'f')' );
%plot errors
e = ones(1,6) * 0.05;
errorbar(x, e,'.r');
set(gca, 'FontSize', 14, 'YLim', [ 0 (max(x) + max(e) + 0.1) ]);
See Coloring 2-D Bars According to Height in the MATLAB documentation. Only the first colour of the colormap is used to colour the faces, you need a bit of hack (as per code on that doc page) to do what you want.