收到的鲜花

• meteora1106 于 2008-11-09 19:52 送鲜花  49朵   附言：好文章

仁兄，你给大家简要介绍一下么，这是个什么东东。

% Gridfit demo script

% This script file is designed to be used in cell mode
% from the matlab editor, or best of all, use the publish
% to HTML feature from the matlab editor. Older versions
% of matlab can copy and paste entire blocks of code into
% the Matlab command window.

Topographic dataload bluff_data;
x=bluff_data(:,1);
y=bluff_data(:,2);
z=bluff_data(:,3);
% Two ravines on a hillside. Scanned from a
% topographic map of an area in upstate New York.
plot3(x,y,z,'.')


% Turn the scanned point data into a surface
gx=0:4:264;
gy=0:4:400;
g=gridfit(x,y,z,gx,gy);
figure
colormap(hot(256));
surf(gx,gy,g);
camlight right;
lighting phong;
shading interp
line(x,y,z,'marker','.','markersize',4,'linestyle','none');
title 'Use topographic contours to recreate a surface'


Fitting a trigonometric surfaceclear

n1 = 15;
n2 = 15;
theta = rand(n1,1)*pi/2;
r = rand(1,n2);

x = cos(theta)*r;
y = sin(theta)*r;
x=x(:);
y=y(:);

x = [[0 0 1 1]';x;x;1-x;1-x];
y = [[0 1 0 1]';y;1-y;y;1-y];
figure
plot(x,y,'.')
title 'Data locations in the x-y plane'


z = sin(4*x+5*y).*cos(7*(x-y))+exp(x+y);

xi = linspace(0,1,51);
[xg,yg]=meshgrid(xi,xi);
zgd = griddata(x,y,z,xg,yg);

figure
surf(xi,xi,zgd)
colormap(hot(256))
camlight right
lighting phong
title 'Griddata on trig surface'
% Note the wing-like artifacts along the edges, due
% to the use of a Delaunay triangulation in griddata.

zgrid = gridfit(x,y,z,xi,xi);

figure
surf(xi,xi,zgrid)
colormap(hot(256))
camlight right
lighting phong
title('Gridfit to trig surface')


The trig surface with highly different scalings on the x and y axesxs = x/100;
xis = xi/100;

ys = y*100;
yis = xi*100;

% griddata has problems with badly scaled data
[xg,yg]=meshgrid(xis,yis);
zgd = griddata(xs,ys,z,xg,yg);

figure
surf(xg,yg,zgd)
colormap(hot(256))
camlight right
lighting phong
title 'Serious problems for griddata on badly scaled trig surface'

% autoscaling on (the default)
zgrids = gridfit(xs,ys,z,xis,yis,'autoscale','on');

% plot the autoscaled result
figure
surf(xis,yis,zgrids)
colormap(hot(256))
camlight right
lighting phong
title 'Gridfit (automatically scaled) on trig surface'


Fitting the "peaks" surfaceclear

n = 100;
x = (rand(n,1)-.5)*6;
y = (rand(n,1)-.5)*6;

z = peaks(x,y);

xi = linspace(-3,3,101);
zpgf = gridfit(x,y,z,xi,xi);

[xg,yg]=meshgrid(xi,xi);
zpgd = griddata(x,y,z,xg,yg,'cubic');

figure
surf(xi,xi,zpgd)
colormap(jet(256))
camlight right
lighting phong
title 'Griddata (method == cubic) on peaks surface'

figure
surf(xi,xi,zpgf)
colormap(hsv(256))
camlight right
lighting phong
title('Gridfit to peaks surface')

能详细的解释一下么？没看懂什么意思。。。

我的理解，gridata是把一块有限大的布铺在数据点上，而这个改进的函数是把一块无限大的木板钉在数据点上，这样看起来不仅曲面很光滑而且可以外推作简单的预报。来自www.。

恩 太有才了 真的不错~

学习一下，谢谢楼主分享成果。

下载了回帖下  顶起

非常好，谢谢你的分享！

程序下载下来应该怎么用啊。。。楼主教教新人吧