Question

Matlab求离散点围成的面积？

r=0.1;
for Gamma=-pi/6:pi/45:pi/6;
for Beta=-pi/6:pi/45:pi/6;
Alpha=atan((sin(Beta).*sin(Gamma))/(cos(Beta)+cos(Gamma)));
XP=-r.*sin(Alpha).*cos(Beta);
YP=(r/2).*(sin(Alpha).*sin(Beta).*sin(Gamma)+cos(Alpha).*cos(Gamma)-cos(Alpha).*cos(Beta));
plot(XP,YP,'r.');
hold on;
end
end
得到截图，我现在要求外边界点围成的面积，怎么做？

Answer 1

r=0.1;

XP=[];

YP=[];

for Gamma=-pi/6:pi/45:pi/6; 

for Beta=-pi/6:pi/45:pi/6;

Alpha=atan((sin(Beta).*sin(Gamma))/(cos(Beta)+cos(Gamma)));

XP0=-r.*sin(Alpha).*cos(Beta);

YP0=(r/2).*(sin(Alpha).*sin(Beta).*sin(Gamma)+cos(Alpha).*cos(Gamma)-cos(Alpha).*cos(Beta));

XP=[XP,XP0];

YP=[YP,YP0];

hold on;

end

end

hold on

[k,area]=convhull(XP,YP);

plot(XP(k),YP(k))

plot(XP,YP,'r.');

area

area =

     2.253606300308809e-04

追问

能帮我稍微简单注释一下下面求面积的部分吗？不是很懂啊，谢谢啊。