chazhi.m

一维插值、二维插值

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%插值

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%一维插值
year = 1900:10:2010;
product = [75.995, 91.972, 105.711, 123.203, 131.669,...
    150.697, 179.323, 203.212, 226.505, 249.633, 256.344, 267.893];
p2005 = interp1(year,product,1950)
x = 1900:1:2010;
y1 = interp1(year,product,x,'cubic');     %三次函数插值
y2 = interp1(year,product,x,'nearest');   %最近邻点插值，直接完成计算
y3 = interp1(year,product,x,'linear');    %线性插值（缺省方式），直接完成计算
y4 = interp1(year,product,x,'spline');    %三次样条函数插值
subplot(2,2,1),plot(year,product,'o',x,y1),title('cubic三次函数插值');
subplot(2,2,2),plot(year,product,'o',x,y2),title('nearest最近邻点插值');
subplot(2,2,3),plot(year,product,'o',x,y3),title('linear线性插值');
subplot(2,2,4),plot(year,product,'o',x,y4),title('spline三次样条函数插值');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%二维插值
x = 1:6; y = 1:4;  %给出自变量
t = [12 10 11 11 13 15;16 22 28 35 27 20;...
    18 21 26 32 28 25;20 25 30 33 32 30];    %注意t的维数和x，y的维数之间的关系
figure;
subplot(2,3,1),mesh(x,y,t),title('值前的温度分布图');                  %画出插值前的温度分布图
x1 = 1:0.1:6;               %将x细化为51个点
y1 = 1:0.1:4;               %将x细化为31个点
[x2,y2] = meshgrid(x1,y1);         %产生51行51列网络数据点，这一步不可省
t1 = interp2(x,y,t,x2,y2,'cubic');
t2 = interp2(x,y,t,x2,y2,'nearest');
t3 = interp2(x,y,t,x2,y2,'linear');
t4 = interp2(x,y,t,x2,y2,'spline');
subplot(2,3,2),mesh(x1,y1,t1),title('cubic三次函数插值');
subplot(2,3,3),mesh(x1,y1,t2),title('nearest最近邻点插值');
subplot(2,3,4),mesh(x1,y1,t3),title('linear线性插值');
subplot(2,3,5),mesh(x1,y1,t4),title('spline三次样条函数插值');

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%三维数据插值
[x,y,z,v] = flow(20);  %flow是MATLAB提供的水下射流速度数据
[xx,yy,zz] = meshgrid(0.1:0.25:10,  -3:0.25:3,  -3:0.25:3);
vv = interp3(x,y,z,v,xx,yy,zz);
shading interp   %用线性插值法处理图像颜色的浓淡
colormap cool    %青红浓淡色图 
%不知道为什么显示不了图