How to make the quiver() arrow head size fixed?

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Felipe  Schuback
Felipe Schuback on 28 Aug 2017
Commented: Iuliu Ardelean on 7 Jun 2022
Hi all-
When I use the quiver() function to plot an arrow in my scatterplot, I noticed that the size of the arrow head is different, depending on how big the arrow itself is (its length basically).
Any ideas on how to make the arrow head size fixed independent of the arrow length? Or if it is at least possible to do?
Best.
  1 Comment
muhkuhmw
muhkuhmw on 16 Oct 2017
Did you find a good solution? I am struggling with the same problem. I willl possible try this: stackoverflow - In Matlab how do I change the arrow head style in quiver plot?

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Answers (3)

KSSV
KSSV on 29 Aug 2017
  3 Comments

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V.G. de Bie
V.G. de Bie on 14 Nov 2017
Just divide MaxHeadSize by the length of the arrow, then the heads will be the same size.
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broken_arrow
broken_arrow on 24 Sep 2021
Edited: broken_arrow on 27 Sep 2021
I agree quiver and quiver3 should have a built in option for constant arrow head size (@MathWorks Support Team). Dividing by the length doesn't work properly for me (doesn't really yield a constant head size). Here is a function I wrote to solve the problem for quiver3:
function out_arrowhandles =...
quiver3addarrowheads(in_quivhandle,in_arrowheadlength,in_arrowtipangle)
% Adds arrow heads with constant size to quiver3 plot.
% Arrow heads have the same inclination relative to the z plane as the vectors.
%
% Input arguments:
% in_quivhandle: Handle of quiver plot to be appended
% in_arrowheadlength: Desired arrow head length in vector length units
% in_arrowtipangle: Desired arrow head tip angle in degrees (°)
%
% Output arguments:
% out_arrowhandles: Handles to arrow head lines
X = reshape(in_quivhandle.XData,1,[]);
Y = reshape(in_quivhandle.YData,1,[]);
Z = reshape(in_quivhandle.ZData,1,[]);
U = reshape(in_quivhandle.UData,1,[]);
V = reshape(in_quivhandle.VData,1,[]);
W = reshape(in_quivhandle.WData,1,[]);
aux_Xend = X + U;
aux_Yend = Y + V;
aux_Zend = Z + W;
aux_orthvectors = cross([U;V;W],[U;V;W+1]);
aux_orthvectors = aux_orthvectors ./ vecnorm(aux_orthvectors);
if ~any(aux_orthvectors,1)
aux_orthvectors(:,~any(aux_orthvectors,1)) = [1;0;0];
end
aux_arrowtips1 = in_arrowheadlength * (-[U;V;W] ./ vecnorm([U;V;W]) -...
tand(in_arrowtipangle)*aux_orthvectors);
aux_arrowtips2 = aux_arrowtips1 +...
2*in_arrowheadlength*tand(in_arrowtipangle)*aux_orthvectors;
aux_arrowhandle1 = quiver3(in_quivhandle.Parent,aux_Xend,aux_Yend,aux_Zend,...
aux_arrowtips1(1,:),aux_arrowtips1(2,:),aux_arrowtips1(3,:),...
'LineWidth',in_quivhandle.LineWidth,'Color',in_quivhandle.Color,...
'ShowArrowHead','off','AutoScale','off');
aux_arrowhandle2 = quiver3(in_quivhandle.Parent,aux_Xend,aux_Yend,aux_Zend,...
aux_arrowtips2(1,:),aux_arrowtips2(2,:),aux_arrowtips2(3,:),...
'LineWidth',in_quivhandle.LineWidth,'Color',in_quivhandle.Color,...
'ShowArrowHead','off','AutoScale','off');
out_arrowhandles = [aux_arrowhandle1 aux_arrowhandle2];
end
Run the function directly after quiver3 (with 'AutoScale' and 'ShowArrowHead' set to 'off') or combine both into a customquiver3 function if you want an all in one solution. To adapt the function for 2D quiver, append your 2D input vectors by Z=W=0 (cross only works on 3D vectors) and discard the z coordinate (0) before plotting. If you want a different inclination of the arrow heads, modify the cross product accordingly.
Also note that the arrow heads will look "skewed" if daspect of x and y axis differs.
  3 Comments
Rik
Rik on 24 Sep 2021
It has documentation and a rudimentary form of input validation, I woul say that makes it more polished than a third of the submissions. You don't have to go to the same lengths as I currently do before getting on the file exchange.
But it's your call of course.

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