MATLAB: How to find point of intersection

intersectionpoint of intersection

I have 4 coordinate and need to find the point of intersection. Can someone share the coding to find the intersection point and to display the point in graph below. Thank You.

Best Answer

Try this:

blue = [1 5; 1 5];                      % [x1 x2; y1 y2] 

red = [1 5; 3 2];                       % [x1 x2; y1 y2] 
Bb = [blue(1,:)' ones(2,1)] \ blue(2,:)'
Br = [red(1,:)' ones(2,1)] \ red(2,:)'
xint = (Br(2) - Bb(2)) / (Bb(1) - Br(1))
yint = [xint 1] * Bb
figure
plot(blue(1,:)', blue(2,:)', '-b')
hold on
plot(red(1,:), red(2,:), '-r')
plot(xint, yint, 'pg', 'MarkerSize',10)
hold off

producing:

xint =
    2.6000
yint =
    2.6000

Related Solutions

MATLAB: Multiple bar charts with different baselines

You can plot the vertical lines using the plot function. The ‘trick’ is to duplicate the x and y values as matrix arguments:

% line plot
x1=1:10;
y1=1:10;
%bar 1 data
xb1 = [2 5 7];
yb1 = [4 4 4]; 
%bar 2 data
xb2 = [1 2 9];
yb2 = [2 2 2];
figure
p1 = plot(x1,y1);
hold on
b1 = plot([xb1; xb1], [yb1-2; yb1],'-b');
b2 = plot([xb2; xb2], [yb2-6; yb2],'-r');
axis([0  10    ylim])

You will likely need to experiment to get the result you want, but this should give you a start.

MATLAB: Get the intersection points in the graph

Try this:

x = [1,2,3,4,6,7,9,12,14,15,17,18,19];
y = [0,2,4,5,7,9,10,8.5,6,4,2,1.5,0];
yline = 1;
zci = @(v) find(v(:).*circshift(v(:), [-1 0]) <= 0);                                        % Returns Approximate Zero-Crossing Indices Of Argument Vector(y);
idx = zci(y - yline);                                                                       % Indices Near ‘y=1’
for k1 = 1:numel(idx)
    xint(k1) = interp1(y(idx(k1):idx(k1)+1),x(idx(k1):idx(k1)+1),yline,'linear','extrap');  % Find ‘x’ At ‘y=1’
end
RegionArea = trapz(x,y-yline)
figure(1)
plot(x, y)
hold on
plot(x, ones(size(x))*yline)
plot(xint, ones(size(xint))*yline, 'pg', 'MarkerSize',10)
hold off
legend('Data', 'y = 1', 'Intersection Points', 'Location','NE')
text(6, 4, sprintf('Area = %.2f', RegionArea))

Best Answer

Related Solutions

MATLAB: Multiple bar charts with different baselines

MATLAB: Get the intersection points in the graph

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