matlab程序曲面拟合.docx

%Gridfitdemoscript

%Thisscriptfileisdesignedtobeusedincellmode
%fromthematlabeditor,orbestofall,usethepublish
%toHTMLfeaturefromthematlabeditor.Olderversions
%ofmatlabcancopyandpasteentireblocksofcodeinto
%theMatlabcommandwindow.
Topographicdata
loadbluff_data;
x=bluff_data(:,1);
y=bluff_data(:,2);
z=bluff_data(:,3);
%Tworavinesonahillside.Scannedfroma
%topographicmapofanareainupstateNewYork.
plot3(x,y,z,'.')

%Turnthescannedpointdataintoasurface
gx=0:4:264;
gy=0:4:400;
g=gridfit(x,y,z,gx,gy);
figure
colormap(hot(256));
surf(gx,gy,g);
camlightright;
lightingphong;
shadinginterp
line(x,y,z,'marker','.','markersize',4,'linestyle','none');
title'Usetopographiccontourstorecreateasurface'

Fittingatrigonometricsurface
clear

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=[[0011]';x;x;1-x;1-x];
y=[[0101]';y;1-y;y;1-y];
figure
plot(x,y,'.')
title'Datalocationsinthex-yplane'

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))
camlightright
lightingphong
title'Griddataontrigsurface'
%Notethewing-likeartifactsalongtheedges,due
%totheuseofaDelaunaytriangulationingriddata.

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

figure
surf(xi,xi,zgrid)
colormap(hot(256))
camlightright
lightingphong
title('Gridfittotrigsurface')

Thetrigsurfacewithhighlydifferentscalingsonthexandyaxes
xs=x/100;
xis=xi/100;

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

%griddatahasproblemswithbadlyscaleddata
[xg,yg]=meshgrid(xis,yis);
zgd=griddata(xs,ys,z,xg,yg);

figure
surf(xg,yg,zgd)
colormap(hot(256))
camlightright
lightingphong
title'Seriousproblemsforgriddataonbadlyscaledtrigsurface'

%autoscalingon(thedefault)
zgrids=gridfit(xs,ys,z,xis,yis,'autoscale','on');

%plottheautoscaledresult
figure
surf(xis,yis,zgrids)
colormap(hot(256))
camlightright
lightingphong
title'Gridfit(automaticallyscaled)ontrigsurface'
Warning:Duplicatex-ydatapointsdetected:usingaverageofthezvalues.

Fittin