Patch function doesnt shade the second plot.

Hello, I am trying to plot 2 datasets on the same plot. I have 2 data sets that contain of means and standard deviations. I want to plot them so that the mean is plotted as a line plot and the standard deviation is plotted as a shaded area around it. I am using the patch function and i am able to get this done for one data set but when i try to do it for the second data set, the patch function doesnt shade in the area between the standard deviation, rather it just plots the standard deviation as 2 lines.

This is the code I am using.

plot(time,meanND);

Unrecognized function or variable 'time'.

hold on; 
patch([time fliplr(time)], [meanND-stdev  fliplr(meanND+stdev)], 'r', 'FaceAlpha',0.2, 'EdgeColor','none');
hold on;

plot(time, meanNDtest);
hold on;
patch([time fliplr(time)], [meanNDtest-stdevtest  fliplr(meanNDtest+stdevtest)], 'r', 'FaceAlpha',0.2, 'EdgeColor','r');
hold off

I dont understand what I am doing wrong. Any help will be appreciated. I tried changing the patch arguments for the second plot. Nothing changes the shaded region. I am only able to change the opacity of the standard deviation lines.

Answer 1

[Star Strider]

One of those vectors in the second plot likely has at least one NaN value.

Try something like this —

meanNDtest = fillmissing(meanNDtest, 'nearest');

stdevtest = fillmissing(stdevtest, 'nearest');

I have no idea where it is in your data, however I can reproduce the error you are getting by putting it at the end of the ‘ym’ vector here —

x = 1:10;
ym = rand(1,10);
ysd = 0.1+rand(1,10)/10;

figure
plot(x, ym, '-')
hold on
patch([x flip(x)], [ym+ysd flip(ym-ysd)],'r', 'FaceAlpha',0.5, 'EdgeColor','none')
hold off
title('Without NaN')

ym(10) = NaN;                                                               % NaN In 'ym'

figure
plot(x, ym, '-')
hold on
patch([x flip(x)], [ym+ysd flip(ym-ysd)],'r', 'FaceAlpha',0.5, 'EdgeColor','r')
hold off
title('With NaN')

If there is a NaN value in any of the patch arguments, the patch will not plot.

See the documentation on fillmissing for details.

.

[Tejas Mahadevan]

that did it. there was a NaN value in the dataset. I did not know NaN values would cause this issue. Thank you so much for your help. I really appreciate it.

[Star Strider]

As always, my pleasure!