Placing annotations at specific xy coordinates

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Vance Blake
Vance Blake le 13 Sep 2019
Commenté : DGM le 22 Avr 2025 à 3:26
Just wondering but I wanted to put annotations/text boxes at specific coordinates but when I read up on the page I saw that the values of x and y in the 'dim' vector must be between 0 and 1. Im just looking for a way to place 'X's at specific xy coordinates to signify that those points are no longer being considered for my calculations?? I figured annotations would be good way to accomplish that because I wanted to avoid matlab cconsidering a plotted X as an active point and therefore valid for my calculations. If you have any work arounds or suggestions Im all ears. Thanks for the help

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Adam Danz
Adam Danz le 13 Sep 2019
Modifié(e) : Adam Danz le 21 Avr 2025 à 20:54
Annotation objects are designed to annotation the figure space in figure coordinates. They are not designed to be positioned within axes coordinates. For axes and data coordinates, using axes objects such as rectangle or text.
hold on
plot(x,y,'rx')
If you wanted rectangles for whatever reason,
widthHeight = [.1,.1];
rectangle('Position', [x-widthHeight(1)/2, y-widthHeight(2)/2, widthHeight])
  5 commentaires
Adam Danz
Adam Danz le 14 Sep 2019
Vance Blake
Vance Blake le 16 Oct 2019
Hey Adam how are you ? Its been a while but I have some more questions that I would really like your help with when you get the chance the link to the question is below. https://www.mathworks.com/matlabcentral/answers/485730-define-an-if-statement-based-on-on-finding-duplicate-values-between-arrays-and-then-rewrite-code-to

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Plus de réponses (4)

Olle Trollberg
Olle Trollberg le 29 Août 2023
I recently ran into this and here is a simple way to get around it using some anonymous functions to do rescaling.
Works at least in 2022b
plot(x,y) % Create whatever plot
ax = gca;
% Define helper funcitons to normalize from axis coordinates to normalized position in figure.
xnorm = @(x)((x-ax.XLim(1))./(ax.XLim(2)-ax.XLim(1))).*ax.InnerPosition(3)+ax.InnerPosition(1)
ynorm = @(y)((y-ax.YLim(1))./(ax.YLim(2)-ax.YLim(1))).*ax.InnerPosition(4)+ax.InnerPosition(2)
annotation('textarrow',xnorm(x_in_axis_coordinates),ynorm(y_in_axis_coordinates),'string','Arrow Text');

Image Analyst
Image Analyst le 13 Sep 2019
No, not true. If you want to place annotation text onto a plot you can use text() using the x,y that's used for that plot, whatever range it might have, which can be more than 1.
Have you tried
badIndexes = .......whatever you need to do to identify "points are no longer being considered for my calculations"
hold on
plot(x(badIndexes), y(badIndexes), 'rx', 'MarkerSize', 15, 'LineWidth', 2) % Overlay big red X's

Dmitrij Usov
Dmitrij Usov le 16 Avr 2025
f = figure;
an = annotation('arrow');
an.Parent = f.CurrentAxes;
an.X = [0 1];
an.Y = [0 1];
  3 commentaires
Adam Danz
Adam Danz le 21 Avr 2025 à 21:02
Also watch out for axes direction.
Note that assigning axes to the annotation's parent is undocumented.
% some fake data to plot
x = linspace(0,1.5,100);
plot(x,x.^2); hold on
plot(x,sqrt(x))
xlim([0 1.5])
ylim([0 1.5])
set(gca,'YDir','Reverse') % <-------------------Added
% a text box hanging out of the axes
an1 = annotation('textbox');
an1.Parent = gca;
an1.String = 'the curves cross here';
an1.HorizontalAlignment = 'center';
an1.VerticalAlignment = 'middle';
an1.Position = [1.1 0.95 0.6 0.08];
an1.BackgroundColor = [1 1 0];
% a text arrow doing the same
an2 = annotation('textarrow');
an2.Parent = gca;
an2.String = 'the curves cross here';
an2.HorizontalAlignment = 'left';
an2.VerticalAlignment = 'top';
an2.X = [1.15 1];
an2.Y = [0.8 1];
% another arrow pointing to something beyond ylim
an3 = annotation('textarrow');
an3.Parent = gca;
an3.String = 'this line keeps going';
an3.HorizontalAlignment = 'center';
an3.VerticalAlignment = 'top';
an3.X = [0.5 1.5];
an3.Y = [1.1 1.5^2];
DGM
DGM le 22 Avr 2025 à 3:26
Oh wow. That is a problem.

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Bruno Luong
Bruno Luong le 14 Sep 2019
There are several tool on File Exchange, such as this one

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