# plot 3D point data

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ha ha on 23 Nov 2018
Commented: Rik on 24 Nov 2018
I have matrix A=[x y z] with 2112 point data . Please see attachment file, and figure:
How can I plot the surface using that data as the illustration figure?

Rik on 23 Nov 2018
Edited: Rik on 23 Nov 2018
You should be able to use the surf function. The only problem you have is interpolating the data to a normal grid that surf understands (and fill the rest with NaN).
The code below assumes your text file is stored in a 2112 by 3 array named data
x=data(:,1);
y=data(:,2);
z=data(:,3);
SamplePerDim=500;
X=linspace(min(x),max(x),SamplePerDim);
Y=linspace(min(y),max(y),SamplePerDim);
[X,Y]=ndgrid(X,Y);
F=scatteredInterpolant(x,y,z,'linear','none');
Z=F(X,Y);
figure(1),clf(1)
surf(X,Y,Z,'EdgeColor','none')
view(-160,80)
ha ha on 24 Nov 2018
Edited: ha ha on 24 Nov 2018
I try your code. It's good. May i ask you a favor? What is the best number of "SamplePerDim" ? And, How to choose automatically the best number of "SamplePerDim" based on number of the input data? Since when I try with small value of "SamplePerDim=100". The result figure is not good
Rik on 24 Nov 2018
As always, you're welcome.
I don't really know how to pick the resolution automatically. That will depend on the smoothness of your data and how much data you have. Ideally you would 2000, but that makes the plot very slow. You could use a fancy formula to estimate the best value, but because that is tricky I chose to hard code the value.