How to display coordinates of points in "contourf"?

I have three matrices, X, Y, and Z. I am creating a filled contour plot using the command

contourf(X,Y,Z)

How can I display the coordinates of all points in the plot? I can use "Data Cursor" in figure environment to mark coordinates of points individually but this may take a lot of time depending on the number of points.

[jonas]

What do you mean by displaying coordinates? The coordinates are given by the y- and x-axes and the z-value is given by the colorbar.

[Ali Baig]

Dear Jonas,

Thank you for your comment.

What I want to do is have a text box with all points showing their coordinates. Is there any built-in function for this?

[jonas]

Still unclear. Do you want to overlay the contourf with a grid showing all coordinates, like [x1,y1]? All coordinates included?

[Ali Baig]

Yes! this is exactly what I want to do. Thank you!

Answer 1

[jonas]

It's going to look real messy when you have high resolution x and y data.

%%Some data
[x,y,z]=peaks(20);
[~,c]=contourf(x,y,z);hold on
set(gca,'XTick',[],'YTick',[]);

%%Create cell array with coordinates
C = reshape([x(:)'; y(:)'], [], 1)';
str=sprintf('[%.2g;%.2g],',C);
str=strsplit(str,',')
str(end) = [];

%%Plot labels
text(x(:),y(:),str(:),'fontsize',6,'horizontalalignment','center','verticalalignment','mid')

Or alternatively, with the undocumented sprintfc (courtesy Walter Roberson)

%%Same code as above, until:
str=sprintfc('[%.2g;%.2g]',C);
text(x(:),y(:),str(:),'fontsize',6,'horizontalalignment','center','verticalalignment','mid')

[Walter Roberson]

A portion of that could be optimized in that text() accepts multiple coordinates and cell array of character vectors. But then you need to do a vectorized sprintf to generate the character vectors.

[jonas]

Oh, I tried multiple inputs at first. Guess I used the wrong syntax. Sometimes I should take my own advice and read the doc :)

Will update the solution

[Walter Roberson]

sprintfc() might come in handy. Unfortunately it is undocumented.

[jonas]

Managed to do it with sprintf, although it was a bit of a hassle. Will definitely look into sprinfc! Thanks

Answer 2

[Afshin Aghayan]

you can use this code for displaying any data in the form of [x, y, f(x,y)] or data with coordinate

https://www.mathworks.com/matlabcentral/fileexchange/72970-display-data-in-form-of-f-x-y-as-map-and-convert-to-matrix