How to fit a surface to 3D dta points

Question

Mos_bad 2018-9-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418979-how-to-fit-a-surface-to-3d-dta-points

评论： Stephen23 2018-9-14

surface.m

Please find the attached. I want to fit a surface to show the trends of the 3d data points but I got an error that 'Z must be a matrix, not a scalar or vector'.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Stephen23 2018-9-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418979-how-to-fit-a-surface-to-3d-dta-points#answer_336788

编辑：Stephen23 2018-9-14

在 MATLAB Online 中打开

Your data are scattered, not gridded:

https://www.mathworks.com/help/matlab/math/overview-of-interpolation-techniques.html

surf only plots gridded data. To use surf you will either have to

interpolate the values onto a grid, or
fit a curve get gridded values and plot them.

Another option would be to use a Delaunay triangulation to plot the scattered data directly:

trisurf(delaunay(IM,Z50),IM,Z50,MnXdisp)

Gives:

This blog gives an nice explanation of options for scattered data:

http://wspr.io/matlab/delaunay-surf

2 个评论
显示无隐藏无

Mos_bad 2018-9-14

the data abe been like these first : Z50_ = linspace(0,20,20); IM_ = linspace(0.0025,1.2,20); [IM, Z50] = meshgrid(IM_, Z50_); Therefore, at each IM or Z50, there are 10 data from MnXdisp data set. I wonder if it is possible to fit 20 curves and then plot a surface.

Stephen23 2018-9-14

@Mos_bad: well, the data you gave us might have been gridded at some point in history, but is now missing many data points. If you have data then of course you can fit curves to it (if that has any meaning depends on the data and what it represents).

请先登录，再进行评论。

Answer 2

KSSV 2018-9-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418979-how-to-fit-a-surface-to-3d-dta-points#answer_336789

编辑：KSSV 2018-9-14

在 MATLAB Online 中打开

% Unstructred data plot 
dt = delaunayTriangulation(IM,Z50) ;
t = dt.ConnectivityList ;
p = dt.Points ;
figure (1);
plot3(IM,Z50,MnXdisp,'b*');
hold on; 
trisurf(t,p(:,1),p(:,2),MnXdisp')
title('unstructured')
% structured plot 
x = IM ; y = Z50 ; z = MnXdisp ;
N = 50 ;
xi = linspace(min(x),max(x),N) ;
yi = linspace(min(y),max(y),N) ;
[X,Y] = meshgrid(xi,yi) ;
Z = griddata(x,y,z,X,Y) ;
figure (2);
plot3(IM,Z50,MnXdisp,'b*');
hold on; 
surf(X,Y,Z)
title('structured')