6-21.m

《MATLAB 7.0编程基础》第6章 （源码实例）主要讲解MATLAB图形基础

wdir = [45 90 90 45 360 335 360 270 335 270 335 335];
knots = [6 6 8 6 3 9 6 8 9 10 14 12];
rdir = wdir * pi/180;
[x,y] = pol2cart(rdir,knots);
subplot(221)
compass(x,y)
subplot(222)
t = 0:0.5:10;
s = 0.05+i;
Z = exp(-s*t);
feather(Z)
subplot(223)
[X,Y] = meshgrid(-2:.2:2);
Z = X.*exp(-X.^2 - Y.^2);
[DX,DY] = gradient(Z,.2,.2);
% 梯度计算
contour(X,Y,Z)
% 轮廓图绘制，下一小节中说明此函数
hold on
quiver(X,Y,DX,DY)
% 箭头图绘制
grid off
hold off
subplot(224)
Z = X.* exp(-X.^2 - Y.^2);
[U,V,W] = surfnorm(X,Y,Z);
% 计算图形的法线
quiver3(X,Y,Z,U,V,W,0.5);
hold on
surf(X,Y,Z);
hold off