Shading the Standard Deviation

I have this graph, with the plotted mean and +-Std Dev. I need to shade the area between the upper and lower deviation. I have tried fill and area but they create very distorted images.

Any guidance would be appreciated.

[darova]

Please attach the data and your code

[Image Analyst]

Logan, read this link. And see my and Star's answers below.

Shading between curves is in the FAQ. (I just added it.)

https://matlab.fandom.com/wiki/FAQ#How_do_I_shade_the_region_between_two_curves.3F

[Logan Thurston]

Heres the data, and my code.

Answer 1

[Star Strider]

Try this (obviously with your data, not my simulated vectors):

x = 1:50;                                                       % Create: ‘x’ Data
y = randi([100 150], size(x));                                  % Create: ‘y’ Data
sd = 10*rand(size(x));                                          % Create: Standard Deviation Vector

figure
plot(x, y)
hold on
patch([x fliplr(x)], [y-sd  fliplr(y+sd)], [0.6  0.7  0.8])
hold off

That will work for both of your data sets. Use a separate patch call for each one.

If your data ar column vectors ratther than the row vectors in my simulation, vertically concatenate them using the semicolon (;) and use flipud instead of fliplr.

Example —

patch([x(:); flipud(x(:))], [y(:)-sd(:);  flipud(y(:)+sd(:))], [0.6  0.7  0.8])

(The (:) subscript convention forces them to be column vectors.)

EDIT — (30 Mar 2020 at 17:17)

The ‘t’ vector must be forced to be a column vector for the code to work, since all the rest are column vectors:

figure(1)
plot(t(:),(NSDR1),'r'); 
hold on;
plot(t(:),(PSDR1),'r');
patch([t(:); flipud(t(:))],[NSDR1; flipud(PSDR1)], 'r', 'FaceAlpha',0.2, 'EdgeColor','none');
hold off

[Logan Thurston]

I get an error with vector length, but nothing i can see looks like its longer? I attatched my data and code if you want to take a look. Appreciate the help.

[Logan Thurston]

I have converted t into a colum vector by doing t=t'; but i still get the same error. All my values in the workpsace are 8000x1 column vectors.

Edit- I also tried using the (:) convention prior to transposing with t' but no dice.

[Star Strider]

The code I posted (the last part derived from your code) ran without error.

Please use the code I posted.

If you also want the ‘Block1’ mean value to appear, add that plot call:

figure(1)
plot(t(:),(NSDR1),'r'); 
hold on;
plot(t(:),(PSDR1),'r');
patch([t(:); flipud(t(:))],[NSDR1; flipud(PSDR1)], 'r', 'FaceAlpha',0.2, 'EdgeColor','none');
plot(t(:), Block1, 'r')
hold off

That code produces this plot:

The complete code:

Assignment = load('Assignment(2).txt');
Fs=2048;


%2- Isolate Trails 1-5, 21-25

MVC1=Assignment(:,1:5);
MVC2=Assignment(:,21:25);
t=[1:length(MVC1)]*(1/Fs);
Block1=mean(MVC1,2);
Block2=mean(MVC2,2);

SD1=std(MVC1,0,2);
SD2=std(MVC2,0,2);
NSDR1=(Block1-SD1);
PSDR1=(Block1+SD1);

figure(1)
plot(t(:),(NSDR1),'r'); 
hold on;
plot(t(:),(PSDR1),'r');
patch([t(:); flipud(t(:))],[NSDR1; flipud(PSDR1)], 'r', 'FaceAlpha',0.2, 'EdgeColor','none');
plot(t(:), Block1, 'r')
hold off

Answer 2

[Image Analyst]

Here's a general purpose demo that you can adapt as needed.

% Shades region between two curves with light green.
% Initialization steps.
clc;    % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format short g;
format compact;
fontSize = 15;

numPoints = 600;
x = 1 : numPoints;
% Make and plot y1.
period1 = 300;
y1 = cos(2 * pi * x / period1);
% plot(x, y1, 'r-', 'LineWidth', 3);

% Make and plot y2.
period2 = 100;
y2 = cos(2 * pi * x / period2);
hold on;
% plot(x, y2, 'b-', 'LineWidth', 3);
grid on;

% Shade the area between in light green using the patch() function.
lightGreen = [0.85, 1, 0.85];
% Create the boundaries of the upper points and the lower points.
% Assume y1 and y2 have the same number of elements located at the same x values.
upperBoundary = max(y1, y2);
lowerBoundary = min(y1, y2);
% Now do the actual display of the shaded region.
patch([x fliplr(x)], [upperBoundary  fliplr(lowerBoundary)], lightGreen); 

% Plot y1 and y2 AFTER the patch so the patch does not cover any of those curves.
hold on;
plot(x, y1, 'r-', 'LineWidth', 2);
plot(x, y2, 'b-', 'LineWidth', 2);
legend('Patch', 'y1', 'y2');
xlabel('X', 'FontSize', 24);
ylabel('Y', 'FontSize', 24);

% Maximize the figure window
g = gcf; % Doesn't work on gcf directly for some reason.
g.WindowState = 'maximized'