How can I show a certain value in a certain position in the figure?

Hello,

I want to a specific value in the figure. I put the black circle and arrow manually through the figure insert option. But How can I set the value now?

I want the x-axes values that are exactly 90% of each CDF curve.

here I am attaching my matlab figure in jpg mode.

Answer 1

[Mark Sherstan]

Here is a quick example. If you do not have an equation you can still solve for the 0.9 value using numerical methods but the key is the text function.

% Some equation 
syms x
eq = 0.2*x;

% Solve for x coord 
S = vpasolve(eq == 0.9, x)

% Plot
fplot(eq)

% Add labels
hold on
plot(S, 0.9, 'o')
text(S, 0.9, string(S))
hold off

[Tania Islam]

Actually, I dont have any equation. I have only a long array from where I am counting my CDF and plot it.

I am sorry, I cannot understand your example perfectly.

[Mark Sherstan]

If you just have data use the interp1 function to find the x value that corresponds to your y value. So it would look something like this:

% X and y values for one data series
x = [...] 
y = [...] 

% Interpolate the x value for a y value of 0.9
xq = interp1(y,x,0.9)

% Plot the data
plot(x,y)

% Add a circle and text at the area of interest
hold on 
plot(xq, 0.9, 'o')
text(xq, 0.9, string(xq))
hold off

You may want to use a different interpolation method depending on how accurate you need the labels and how many data points you have. Read the documentation in the link I provided for more information.

[Tania Islam]

Thank you so very much for your kind reply.

It works fine for the smaller dataset when I checked it. But when I am trying use in my dataset I am having problem. Like data must be unique. Problem is that in my dataset there is no specific point of 0.9. It may 0.980000012 this way. I am attaching here my dataset for your kind considerations.

I am sorry, I went to the link you provided. I can set the range but how can I get that point value which is very very close to 0.9?

[Mark Sherstan]

I dont fully understand your problem. Please post your code as I got an answer that made sense by just interpolating.

[Tania Islam]

Thank you..

[Tania Islam]

This is my code. I generalize my code. I store my original data output into the variabes, X1_axes, Y1_axes, X2_axes and Y_2axes.

Then I am plotting them in the figure. As I marked in the figure, I want to visulaize this data in my figure.

In your last code, it was perfectly work for small data.

Thank you for time and considerations.

[Mark Sherstan]

Try this (I removed your data set, you just need to copy and paste it back in at the start):

% Find values of interest
xq1 = interp1(Y1_axes,X1_axes,0.9);
xq2 = interp1(Y2_axes,X2_axes,0.9);

% Make the main plot
figure('name','figure','NumberTitle','off');
plot(X1_axes, Y1_axes,'-r')
hold on
plot(X2_axes,Y2_axes,'-g')
hold off

% Add first marker
hold on
plot(xq1, 0.9, 'ko')
text(xq1, 0.85, num2str(xq1))
hold off

% Add secound marker
hold on
plot(xq2, 0.9, 'ko')
text(xq2, 0.95, num2str(xq2))
hold off

% Formatting 
xlabel('time error')
ylabel('CDF')
set(gca,'YTick',0:0.1:1)

[Tania Islam]

Thank you so much.

What is the purpose of 0.85 in this line, text(xq1, 0.85, num2str(xq1)) and changed to 0.95 for another line.

Sorry to ask this, as I have more input to plot in the figure.

Why its different in different line?

[Mark Sherstan]

It’s so that the text doesn’t interfere with each other. Just formatting.

[Tania Islam]

Thank you so much

[Tania Islam]

Did you check with my dataset? When I am running this with this data, I am getting the same error like previous. Is there anything that I have to do?

>> xq1 = interp1(Y1_axes,X1_axes,0.9);

Error using griddedInterpolant

The grid vectors must contain unique points.

Error in interp1 (line 151)

F = griddedInterpolant(X,V,method);

[Mark Sherstan]

I had no problem. You can see the plot that I generated a few posts back.

[Tania Islam]

Thank you