How can I draw a line with arrow head between 2 data points in a plot

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Amit K
Amit K on 28 Oct 2014
Edited: Vitaly Fedoseev on 26 May 2021
Hi,
If there are 2 points in XY plane [x1, y1] and [x2, y2] then how can I draw a line with an arrowhead starting from [x1, y1] and ending at [x2, y2]. Basically, I want the plot to look like this:
[x1, y1]--------->[x2, y2]
Preferably, I like the arrow-line to bend (arc) towards the second point.
AK

Accepted Answer

Star Strider
Star Strider on 29 Oct 2014
Edited: MathWorks Support Team on 17 Mar 2021
That’s easy enough with the quiver function:
p1 = [2 3]; % First Point
p2 = [9 8]; % Second Point
dp = p2-p1; % Difference
figure
quiver(p1(1),p1(2),dp(1),dp(2),0)
grid
axis([0 10 0 10])
text(p1(1),p1(2), sprintf('(%.0f,%.0f)',p1))
text(p2(1),p2(2), sprintf('(%.0f,%.0f)',p2))
The final zero in the quiver call turns off the automatic scaling.
The arc would be a bit more challenging, depending on what you intend by arc. I would just use the quiver result.

More Answers (5)

Sajeer Modavan
Sajeer Modavan on 14 Mar 2019
Edited: Sajeer Modavan on 14 Mar 2019
t = 1:0.1:10; wo = 1;
x = 2*exp(t*wo).*sin(t*wo);
plot(t,x),hold on
plot([6 6],[-1e5 1e5],'--k','Linewidth',1.4)
plot([8.7 8.7],[-1e5 1e5],'--k','Linewidth',1.4)
ylim([-0.3e5 1e4])
% One arrow from left to right with text on left side
x = [0.74 0.79]; % adjust length and location of arrow
y = [0.3 0.3]; % adjust hieght and width of arrow
annotation('textarrow',x,y,'String',' Growth ','FontSize',13,'Linewidth',2)
% Arrow with two head at both end and text between
y = [0.4 0.4];
Xadj = 1.35; % adjust location of left arrow starting point (the sum of this with 'x' should not be negative)
annotation('textarrow',x,y,'String',' Growth ','FontSize',13,'Linewidth',2)
annotation('textarrow',-x+Xadj,y,'String','','FontSize',14,'Linewidth',2)
% One arrow from left to right with text over it
x = [0.56 0.79]; % adjust length and location of arrow
y = [0.5 0.5];
annotation('textarrow',x,y,'FontSize',13,'Linewidth',2)
annotation('textbox',[.6 .3 .7 .27],'EdgeColor','none','String','Growth','FontSize',13,'Linewidth',2)
  1 Comment
Marius Hammer
Marius Hammer on 26 Apr 2019
Could you give an describtion of how the arrow coordinates are set exactly? x and y need to be between 0 and 1 within annotation, so if I want the arrow to go from e.g. (x1,y1) = (3,0.5) and (x2,y2) = (6,0.5) how is x and y adjusted for exact location?

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Amit K
Amit K on 29 Oct 2014
Edited: Amit K on 29 Oct 2014
Thank you Star Strider.
It did work but how can I make the arrowhead bigger? In addition the head is not facing outward so it head to tell if the head is there.
AK
  1 Comment
Star Strider
Star Strider on 29 Oct 2014
My pleasure!
I don’t know what you mean by ‘the head is not facing outward’. It’s the normal behaviour of the quiver plot. If you want to increase the size of the arrowhead, specify 'MaxHeadSize' as larger than the default value of 0.2. For example:
quiver(p1(1),p1(2),dp(1),dp(2),0, 'MaxHeadSize',0.5)
makes it times larger.

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Amit K
Amit K on 30 Oct 2014
Edited: Amit K on 30 Oct 2014
Thank you guys. It worked but not good enough for what I'm doing with the plots. Is it possible to draw an arc instead of a line between the two point going from the starting point to the end point. The two points are not equidistant from the centre. Appreciate for your help.
AK

Vitaly Fedoseev
Vitaly Fedoseev on 26 May 2021
Edited: Vitaly Fedoseev on 26 May 2021
The following code (Matlab R2019a) draws an arrow in the plot coordinates from point P1 to point P2. Zoom in/out shifts position of the arrow:
P1=[10,-1]; %from point
P2=[70,2]; % to point
figure;
Xlim=[-1 110];
Ylim=[-2 3];
Pos = [0.10 0.55 0.85 0.4];
subplot('Position', Pos)
hold on
X_conv(1)=Pos(1)+(Pos(3))/(Xlim(2)-Xlim(1))*(P1(1)-Xlim(1));
X_conv(2)=Pos(1)+(Pos(3))/(Xlim(2)-Xlim(1))*(P2(1)-Xlim(1));
Y_conv(1)=Pos(2)+(Pos(4))/(Ylim(2)-Ylim(1))*(P1(2)-Ylim(1));
Y_conv(2)=Pos(2)+(Pos(4))/(Ylim(2)-Ylim(1))*(P2(2)-Ylim(1));
x=0:0.1:100;plot(x, sin(x));plot([-100 1000], P2(2)*[1 1]); plot(P2(1)*[1 1], [-100 100]);
plot(x, sin(x));plot([-100 1000], P1(2)*[1 1]); plot(P1(1)*[1 1], [-100 100])
xlim(Xlim)
ylim(Ylim)
annotation('arrow', X_conv, Y_conv)

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