MATLAB利用极坐标转换画相对角度相对长度的线段

Posted 2020-08-15

今天在MATLAB论坛上，有一位坛友要画已知相对角度相对长度的连续线段。

查了一些资料，想了一些办法。发现利用极坐标画向量，再由向量叠加的方式进行绘制就可以解决这个问题。写一个trans_cood函数：

1 function [Lx,Ly] = trans_cood(x,y,RHO,R)  
2 th = [0; RHO*pi/180];  
3 rho = [0; R];  
4 [xvec,yvec] = pol2cart(th,rho);  
5 Lx(1) = x;  
6 Ly(1) = y;  
7 Lx(2) = x + xvec(2);  
8 Ly(2) = y + yvec(2); 

这个函数中pol2cart生成一个起始点为（0，0）,角度由RHO决定，相对长度由R决定的向量。将这个向量与原点相加，得到了所需要的连续线段坐标Lx(2),Ly(2).

例：按下面这个案例画路径图：?

 1 P_x = 0; P_y = 0;  
 2 rectangle(‘Position‘, [0 0 4 4.598]);hold on;  
 3 x = 0 ; y = 0;  
 4 RHO = [90,0,300,60,300,60,300,60,300,90,90,90,180,240,120,240,120,240,120,240,90,90,90,0,300,60,300,60,300,60,0,270];  
 5   
 6 R = [0.866025403784439,0.500000000000000,1,1,1,1,1,1,1,0.866025403784439,1,0.866025403784439,0.500000000000000,1,1,1,1,1,1,1,0.866025403784439,1,0.866025403784439,0.500000000000000,1,1,1,1,1,1,0.500000000000000,0.866025403784439];  
 7 for i = 1 :32  
 8    [Lx,Ly] = trans_cood(x,y,RHO(i),R(i));  
 9    x = Lx(2); y = Ly(2);P_x =[P_x Lx(2)]; P_y = [P_y Ly(2)];  
10 end  
11 axis equal  
12 plot(P_x,P_y,‘o‘,‘markerfacecolor‘,‘r‘,‘markeredgecolor‘,‘k‘,‘markersize‘,10);  
13 H = quiver(P_x(1:end-1),P_y(1:end-1), P_x(2:end) - P_x(1:end-1), P_y(2:end) - P_y(1:end-1));  
14 axis([-0.5 4.5 -0.5 5]);  
15 set(H,‘color‘,‘b‘,‘maxheadsize‘,0.1);  
16 box on;?