如果您想要一个固定的半径,则为它们分配一个恒定值(而不是随机值)并保留方向角度的随机数(azimuth/elevation
或theta/phi
取决于符号)。
这段代码:
rng(0,'twister');
nptSet = 500 ; r1 = 40 ; r2 = 100 ; %// your constraints
%// first data set (r1=40)
r1 = zeros(nptSet,1)+r1 ; %// assign radius (fixed)
azi1 = rand( size(r1) ) * 2*pi ; %// random azimuth [ 0 2pi]
elev1 = (rand(size(r1)) .* pi)-pi/2 ; %// random elevation [-pi/2 pi/2]
%// second data set (r2=100)
r2 = zeros(nptSet,1)+r2 ; %// assign radius (fixed)
azi2 = rand( size(r2) ) * 2*pi ; %// random azimuth [ 0 2pi]
elev2 = (rand(size(r2)) .* pi)-pi/2 ; %// random elevation [-pi/2 pi/2]
%// convert to cartesian
[x1,y1,z1] = sph2cart(azi1,elev1,r1);
[x2,y2,z2] = sph2cart(azi2,elev2,r2);
%// display and refine
figure ; hold on
plot3(x1,y1,z1,'or','MarkerSize',2);
plot3(x2,y2,z2,'+b');
xlabel('x') ; ylabel('y') ; zlabel('z')
axis equal ; grid off ; view(50,30)
会给你这个数字:
