Locate Y given X and display on the graph

Hello ,

I have been trying to display the value of X and Y given either X or Y on my graph but am unable to do so. I would also like to be able to add in additional info/text and be able to re-size the box. The following was done through of the Data Cursor function which is not accurate. Please help , thanks.

Regards , Haziq

Answer 1

[Ilham Hardy]

You can 'extract' the Data Cursor information to workspace for more accurate number. Right click on the data cursor point >> Export cursor data to workspace.

Answer 2

[RuiQi]

Hello ,

Thanks for the response but what I meant was e.g. I would like to find the value of Y when X = 0.3. I have done so by sliding the Data Cursor along the graph to get as close as I can to 0.3 which is not accurate. I apologize for not being clear with my words.

Regards , Haziq

[Sean de Wolski]

To do this correctly, you'd have to get the x/y data from the line and then use interp1 to get you the value of y at x == 3.

Answer 3

[Sean de Wolski]

h = plot(cumsum(rand(1,10)),rand(1,10));

valueICareAbout = 3;
yICareAbout = interp1(h.XData,h.YData,valueICareAbout) % R2014b syntax

Answer 4

[Ilham Hardy]

Refering to your description,

If you generate the graph yourself using plot function, then simply interpolates your xpoint to find the applicable ypoint.

Please see,

doc interp1

[Sean de Wolski]

Even if not generating the plot yourself, you could use findobj to traverse the graphics tree.

[Ilham Hardy]

Yes, very true. (i plan this as 'else' description)

Answer 5

[RuiQi]

Hello ,

Thanks for the function but it seems to not give the correct answer. The graph was plotted using the step() function.

My student research project requires MATLAB. Im sorry, I thought I could just jump straight into modelling and control after going through the tutorial videos but I guess im wrong. I need to learn MATLAB from scratch. This just feels so new.

Regards , Haziq