How to say the third selected point lies within the created geometry or not?

1 visualización (últimos 30 días)
close all
clc
base_x = [0 50 50 20 0 0]
base_y = [0 0 10 10 10 0 ]
roof_x = [ 0 0 20 20 30 30]
roof_y =[ 10 50 10 50 50 10]
figure
plot(base_x, base_y,'-')
hold on
plot(roof_x, roof_y,'-')
axis([0 50 0 50])
grid on
[X,Y]=meshgrid(1:11);
[x] = ginput(2);
[x] = round(x);
fprintf ('the a1 coordinate value is %d,\n' , x(1,1));
fprintf ('the b1 coordinate value is %d ,\n' , x(1,2));
fprintf ('the a2 coordinate value is %d,\n' , x(2,1));
fprintf ('the b2 coordinate value is %d ,\n' , x(2,2));
How to say the third selected points a1,b1 a2,b2 lies within the created geometry ( base,roof) or not?
  4 comentarios
Adam Danz
Adam Danz el 25 de Jul. de 2018
Kaleesh, I'm continuing your other thread (link above) here because this topic seems to be more relevant to the problems you're having.

Iniciar sesión para comentar.

Respuesta aceptada

Adam Danz
Adam Danz el 24 de Jul. de 2018
Editada: Adam Danz el 25 de Jul. de 2018
If I understand your question correctly, you're trying to determine if a coordinate (x,y) lies within a polygon.
First try matlab's inpolygon().
Another way to achieve that is by "ray casting". The idea is to draw a line from the (x,y) coordinate and extend it rightward until it passes all of the possible polygon edges. Then count the number of times that ray intersects with an edge of the polygon. If that number is non-zero and odd, then the coordinate (x,y) is within the polygon.
To achieve that, you'll need to loop through each edge of your polygon and determine if each line segment intersects with the virtual ray. Here's a nice tutorial on how to detect line segment intersection. And here's more info on the ray casting technique.
  5 comentarios
Ramesh Bala
Ramesh Bala el 25 de Jul. de 2018
Editada: Ramesh Bala el 25 de Jul. de 2018
yeah the bottom edge wasn't mentioned in the previous code,but there in the updated one
xv = [0 0 0 20 20 0 10 20 20 20 20 30 30 50 50 20 30 40 50]
yv = [0 0 50 10 0 0 0 0 0 10 50 50 10 10 0 0 0 0 0 ]
let me try to check with these values now Danke /Thanks Adam
Ramesh Bala
Ramesh Bala el 26 de Jul. de 2018
yeah the command worked ,even the previous one also works. for the further case just added frpintf by calling on && in with values to check

Iniciar sesión para comentar.

Más respuestas (0)

Categorías

Más información sobre Line Plots en Help Center y File Exchange.

Etiquetas

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by