MATLAB: Find intersection point of two lines when I have their coordinates

line

I have four COORDINATES of two lines – [x1,y1], [x2,y2], [x3,y3], [x4,y4]. Now, how to get the coordinate of their intersecting point [x,y] ? Any help ??

Best Answer

The result of the three steps I mentioned would be:

xy = [x1*y2-x2*y1,x3*y4-x4*y3]/[y2-y1,y4-y3;-(x2-x1),-(x4-x3)];

I don’t consider that too long or complicated an expression. The xy variable here is a 1-by-2 vector consisting of the x and y coordinates of the intersection.

Related Solutions

MATLAB: Discrete equation with two unknown variables

This can be rewritten as:

a*x1^2 - b*y1 = y1
a*x2^2 - b*y2 = y2

or in matrix form:

A * [a b]' = [y1 y2]'

where:

A = [x1^2 -y1; x2^2 -y2];

So:

x1 = 2;
x2 = 3.3;
y1 = 9;
y2 = 2.9;
A = [x1^2 -y1; x2^2 -y2];
RHS = [y1 y1]';
solution = A\RHS;
a = solution(1);
b = solution(2);

HTH,

Arnaud

MATLAB: To find intersection point of two lines

Hi,

not sure if I understand correctly what you want but is this what you are looking for?

%line1
x1  = [7.8 8.5];
y1  = [0.96 0.94];
%line2
x2 = [8.25 8.25];
y2 = [0 0.99];
%fit linear polynomial
p1 = polyfit(x1,y1,1);
p2 = polyfit(x2,y2,1);
%calculate intersection
x_intersect = fzero(@(x) polyval(p1-p2,x),3);
y_intersect = polyval(p1,x_intersect);
line(x1,y1);
hold on;
line(x2,y2);
plot(x_intersect,y_intersect,'r*')

Best Answer

Related Solutions

MATLAB: Discrete equation with two unknown variables

MATLAB: To find intersection point of two lines

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