how to find intersection point of these graph??

filename = 'gg.csv';
A = xlsread(filename);

filename = 'gg.csv';
sheet = 1;
x1=A(:,1);
y1=A(:,2);


hold on

set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
set(gcf, 'Name', 'champion manufactering', 'NumberTitle', 'Off') 

x2=[0 200 400 700];
y2=[55 65 70 40];
plot(x1,y1);


plot(x2,y2);






hold off

[Rahul punk]

hi matlab community please help for this question.

Answer 1

[KSSV]

Use this file exchange function:

https://in.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections?focused=5165138&tab=function

[Rahul punk]

i already try this method

[KSSV]

It should work for you.......then.

[Rahul punk]

but not work

[Rahul punk]

p=interX([x1:y1],[x2;y2]);

plot(x1,y1 ,x2 ,y2, p(1,:),p(2,:),'ro');

not work

[KSSV]

Your inputs should be L1 and L2. They should be row matrices i.e there order should be 2*n. Check your input or attach the data here.

[Rahul punk]

this is excell data file please write the code kssv

[KSSV]

Only one curve..?

[Rahul punk]

second one is this write in above code

x2=[0 200 400 700];

y2=[55 65 70 40];

plot(x1,y1);

[KSSV]

[num,txt,raw] = xlsread('gg.csv') ;
x1 = num(:,1) ; y1 =  num(:,2) ; 

x2=[0 200 400 700];
y2=[55 65 70 40];

L1 = [x1 y1]' ;
L2 = [x2 ; y2] ; 
P = InterX(L1,L2) ; 

plot(x1,y1,'r') 
hold on
plot(x2,y2,'b')
plot(P(1,:),P(2,:),'*g')

[Rahul punk]

kssv!, sir very thanful for give for valuable time to write code ,no words for your wonderfull help thank so much!

[Rahul punk]

sir one more how to count these intersection point

and code show me error! some time .

Answer 2

[KSSV]

Read about size.

[Rahul punk]

p show some value but i have multiply by 20 and then disp values

[Rahul punk]

m=p*20;

disp(m)

[ARUN]

Hello, I am also trying to get similar kind of intersection points, I used the function InterX but I am not getting all the intersection point.

Below is my plot. I need to find the intersection point of red curve on each horizontal green line. Can you please tell me whether this algorithm(InterX) works for this scenario

[Rahul punk]

http://www.yawot.com/2021/05/05/multiple-curves-and-line-intersection/

[ARUN]

I tried with this, but I am not getting proper intersection points:

Below is the code(attached datapoints)

 P1 = [Xin,Yin]; 
 P2 = [Xout,Yout];
 Xa = [P1(:,1),P2(:,1)];
 Xb = [P1(:,2),P2(:,2)];
 Xa1 = Xa';
 Xb1 = Xb';
 X1 = X';
 Y1 = Y';
 plot(Xa1,Xb1,'g');
 hold on
 plot(X1,Y1)

L1 = [X1;Y1];
L2 = [Xa1; Xb1];
P = InterX(L1,L2);

[KSSV]

You need to proceed like this:

load('VItrack1.mat') 
P1 = [Xin,Yin];

P2 = [Xout,Yout];

Xa = [P1(:,1),P2(:,1)];
Xb = [P1(:,2),P2(:,2)];

Xa1 = Xa';
Xb1 = Xb';

X1 = X';
Y1 = Y';


L1 = [X1;Y1];
L2 = [Xa1; Xb1];
n = size(Xa1,2) ; 
P = NaN(2,n) ; 
for i = 1:n
    L2 = [Xa1(:,i)' ; Xb1(:,i)'] ; 
    p = InterX(L1,L2); 
    if ~isempty(p)
        P(:,i) = InterX(L1,L2);
    end
end

plot(Xa1,Xb1,'g');
hold on
plot(X1,Y1,'b')
plot(P(1,:),P(2,:),'.r')

[ARUN]

Thank you so much for your help! But when I tried the same alogorithm for different datapoints I am getting an error as below:

Unable to perform assignment because the size of the left side is 2-by-1 and the size of the right side is 2-by-3.

Error in Myexample2 (line 69)

P(:,i) = InterX(L1,L2);

Attaching datapoints for your reference.

Could you help me to solve this. Thank you.

[KSSV]

Did you see the if condition with isempty?

[ARUN]

It (p) has value in it. It is not empty.

[KSSV]

Okay in that case, the intersection points are more than one and you are trying to save 2*n matrix into 2*1, so there is error.