![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/175015/image.png)
How can we Plot a line passing through two points?
264 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Emmanuel
le 29 Mai 2014
Commenté : Peter Hansen
le 17 Août 2021
I am given two points (x1,y1) and (x2,y2). How can I plot a line that will pass through these two points and extend till the x and y axis?
0 commentaires
Réponse acceptée
David Sanchez
le 29 Mai 2014
If you want a line connecting A and B:
A = [2 3];
B = [4 5];
plot(A,B,'*')
axis([0 10 0 10])
hold on
line(A,B)
hold off
If you want a line through A and B that extend to the plt limits:
xlim = get(gca,'XLim');
m = (B(2)-B(1))/(A(2)-A(1));
n = B(2)*m - A(2);
y1 = m*xlim(1) + n;
y2 = m*xlim(2) + n;
hold on
line([xlim(1) xlim(2)],[y1 y2])
hold off
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/175015/image.png)
5 commentaires
nobody
le 11 Sep 2020
above meaning connecting the two points P1=[A(1),B(1)] and P2=[A(2),B(2)]
If you want to connect the two points C=[2,3] and D=[4,5] you do
m = (D(2)-C(2)) / (D(1)-C(1)); %slope
n = C(2) - C(1)*m %vertical shift from [0,0]
y1 = m*xlim(1) + n;
y2 = m*xlim(2) + n;
don't you?
Plus de réponses (1)
Mahesh
le 29 Mai 2014
A = (x1,y1); B = (x2,y2);
plot(A,B)
4 commentaires
Adam Danz
le 4 Juin 2021
Modifié(e) : Adam Danz
le 4 Juin 2021
No, this is incorrect. With the syntax plot(A,B), A contains x-values and B contains y-values. Instead, Mahesh defined A and B as (x,y) coordinates.
A simple test will show that this is incorrect,
A = [1,2];
B = [ -3,4];
plot(A,B)
hold on
plot(A(1),A(2), 'r*')
plot(B(1),B(2), 'k*')
legend('line','A','B','Location','BestOutside')
axis padded
To connect coordinates A-B you must use,
plot([A(1),B(1)], [A(2),B(2)])
Peter Hansen
le 17 Août 2021
First of all, you need to understand that mathlab is made for matrixes and arrays, to easy big data calculation.
So all data is ussaly needed in matrix or arrays.
Therfor when ploting points, you dont plot single points like A and B but and array of x-cordinates of A and B and a array of y-cordinates of A and B.
maybe this will claryfy it for you :)
figure(2); clf(2); hold on; axis([0 10 0 10]); axis padded
% If Point A is in x=1 and y=2
% If Point B is in x=-3 and y=4
% If Point C is in x=-6 and y=-4
x_array = [1 -3 -6];
y_array = [2 4 -4];
plot(x_array(1),y_array(1),'*') % A
plot(x_array(2),y_array(2),'*') % B
plot(x_array(3),y_array(3),'*') % C
% OR to plot all points at once uncoment below line insted, and remve ",'B','C'" from legend
% plot(x_array,y_array,'*') % A, B and C
line(x_array,y_array) % line
legend('A','B','C','line','Location','BestOutside') hold off
Voir également
Catégories
En savoir plus sur Visual Exploration dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!