数学建模案例与方法教学课件第5章插值法与拟合方法.ppt

My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template * My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template 5.2 MATLAB与拟合、插值 92 96 97 98 96 93 95 84 82 81 84 85 85 81 82 80 80 81 85 90 93 95 84 86 81 98 99 98 97 96 95 84 87 80 81 85 82 83 84 87 90 95 86 88 80 82 81 84 85 86 83 82 81 80 82 87 88 89 98 99 97 96 98 94 92 87］; mesh(x,y,z) %绘原始数据图 5.2 MATLAB与拟合、插值 xi=linspace(0,5,50); %加密横坐标数据到50个 yi=linspace(0,6,80); %加密纵坐标数据到80个 ［xii,yii］=meshgrid(xi,yi); %生成网格数据 zii=interp2(x,y,z,xii,yii,’cubic’); %插值 mesh(xii,yii,zii) %加密后的地貌图 hold on % 保持图形 ［xx,yy］=meshgrid(x,y); %生成网格数据 plot3(xx,yy,z+0.1,’ob’) %原始数据用o绘出 5.2 MATLAB与拟合、插值 图5-15 例5-8用图2 5.2 MATLAB与拟合、插值 2）二元非等距插值 调用格式：zi=griddata(x,y,z,xi,yi,’指定插值方法’) 插值方法： linear %线性插值(默认) bilinear %双线性插值 cubic %三次插值 bicubic %双三次插值 nearest %最近邻域插值 5.2 MATLAB与拟合、插值 【例5-9】 5.2 MATLAB与拟合、插值 figure(1) mesh(xi,yi,zi) hold on plot3(x,y,z,’o’) figure(2) surf(xi,yi,zi) 用随机数据生成地貌图再进行插值后生成的图形如图5-16所示。 5.2 MATLAB与拟合、插值 图5-16 例5-9用图 该例中使用的数据是随机形成的，故函数griddata可以处理无规则的数据。 感谢聆听 批评指导 * * * My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template My First Template