i have marked 2 example data points (1 and 2) in the end of the T_S_diagram code. the first flow should go from 1 to 2 to 3 to 4 and finnaly to 5
struggeling with the quiver function
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My name is Hidde and i am working on a university project. I need to plot arrows inbetween serveral datapoints. I tried using the quiver function but the headwith gets
all weird. This is because my y axis runs from 0 to 500 and my x axis runs from 0 12. Does somebody know how to fix this? i want arrows with filled arrowheads that are all
the same size and shape regardless of arrow length ect.
i attached the relevant data and matlab files.
6 Comments
Adam Danz
on 6 Jan 2021
Edited: Adam Danz
on 8 Jan 2021
I see what you're describing. A much simpler way to demonstrate this is,
clf()
axes()
endPoint = [5.8, 175]; % [x,y] of arrow end point
headPoint = [7, 200]; % [x,y] of arrow head
plot([endPoint(1),headPoint(1)],[endPoint(2),headPoint(2)],'r*')
xlim([0,12])
ylim([0,500])
grid on
hold on
uv = headPoint - endPoint; % [x,y] distance
quiver(endPoint(1),endPoint(2),uv(1), uv(2),'b-','AutoScale','off')
This is a difficult problem because the quiver() function does not provide a way to change the arrow heads other than to turn them off. The annotation function with the arrow lineType is an alternative but problematic because it only receives corrdinates normalized to the figure (not the axes) so you'd need to compute the normalized position of the arrow and never change the axis limits or ratio.
Accepted Answer
Adam Danz
on 6 Jan 2021
Given the problem described in my comment above, the easiest solution in my opinion is to replace the arrow with a different marker such as a circle and then define which end point of the vector the marker represents.
Here are two examples.
clf()
subplot(2,1,1)
endPoint = [5.8, 175]; % [x,y] of arrow end point
headPoint = [7, 200]; % [x,y] of arrow head
plot([endPoint(1),headPoint(1)],[endPoint(2),headPoint(2)],'r*')
xlim([0,12])
ylim([0,500])
grid on
hold on
uv = headPoint - endPoint; % [x,y] distance
quiver(endPoint(1),endPoint(2),uv(1), uv(2),'b-o','AutoScale','off','ShowArrowHead','off')
text(0,0,'o indicates base of vector in o---', 'VerticalAlignment','bottom')
subplot(2,1,2)
plot([endPoint(1),headPoint(1)],[endPoint(2),headPoint(2)],'r*')
xlim([0,12])
ylim([0,500])
grid on
hold on
uv = endPoint - headPoint; % [x,y] distance
quiver(headPoint(1),headPoint(2),uv(1), uv(2),'b-o','AutoScale','off','ShowArrowHead','off')
text(0,0,'o indicates head of vector in ---o', 'VerticalAlignment','bottom')
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