How to plot individual data on a 2D line graph

I'm being asked to plot the Maximum value of a set of data in a different color and shape from the rest of the line. my code currently looks like this:

subplot(2,1,1)

xdata=[timeh];

y1data=[X];

y1data_max=max(X);

plot(xdata, y1data);

how would i also include y1data_max in my plot in say, a red circle?

Answer 1

[Erivelton Gualter]

See the following example:

% Sample Data
x = 0:.1:2*pi;
y = sin(x);

% Find maximun value
[max_point, idx] = max(y);

figure; hold on; 
plot(x,y); % Fisrt Plot
plot(x(idx), y(idx), 'or') % Red circle at maximum valum

See references:

• https://www.mathworks.com/help/matlab/ref/plot.html
• https://www.mathworks.com/help/matlab/ref/plot.html#btzitot-Marker

[Grace Rembold]

this is fine, but I'm not really sure how to execute this when I make a subplot. Also, this order makes it so the line " plot(x(idx), y(idx), 'or') " supercedes the line " plot(x,y); ". this makes it so on my plot, only the red circle appears on the plot, and the line doesnt.

[Erivelton Gualter]

It is the same for a subplot.

% Sample Data
x = 0:.1:2*pi;
y = sin(x);

% Find maximun value
[max_point, idx] = max(y);
figure; 

% Subplot 1
subplot(211); hold on; 
plot(x,y); % Fisrt Plot

% Subplot 1
subplot(212); hold on; 
plot(x,y); % Fisrt Plot
plot(x(idx), y(idx), 'or') % Red circle at maximum valum

Dont forget to use hold on . It keep the plots , until you use hold off.

https://www.mathworks.com/help/matlab/ref/hold.html

[Erivelton Gualter]

For your code, it might be something like in the following:

xdata=[timeh];
y1data=[X];
y1data_max=max(X);

subplot(2,1,1); hold on;
plot(xdata, y1data);
plot(xdata_max, y1data_max,'or') ;