How to use the inpolygon function ??

Hi Matlab Users,

I have 4 Ponints given

X1=[0,0], X2=[2,0], X3=[2,2] and X4=[0,2]

and one point, lets say P=[1,1], that has to be tested whether it is in the convex hull of X1 to X4. How do i actually do that??

Sry, but i don´t understand the explanation for the inpolygon function when it comes to this simple example above.

http://www.mathworks.de/de/help/matlab/ref/inpolygon.html

I'd appreciate your help, With best regards, john

Answer 1

[Azzi Abdelmalek]

X1=[0,0], X2=[2,0], X3=[2,2],X4=[0,2]
X=[X1(1),X2(1),X3(1),X4(1)]
Y=[X1(2),X2(2),X3(2),X4(2)]
inpolygon(1,1,X,Y) % returns 1 because the point (1,1) is inside the polygon
inpolygon(10,1,X,Y)% %returns 0 because the point (10,1) is outside the polygon

[John]

thank you so much!

[KalMandy]

Hi, Can I use inpolygon to find out if a point lies on the polygon (on one of it's edges/boundaries)?

[Steven Lord]

See the second output argument of the inpolygon function.

[KalMandy]

Found it, Thanks!