how to plot 3D using a txt file

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Nagendra Kamath 2020-9-23

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/598591-how-to-plot-3d-using-a-txt-file

评论： Ameer Hamza 2020-9-23

采纳的回答： Ameer Hamza

chalitp.txt

I want the following graph

I tried using mesh and surf it is showing error that data should be matrix not scalar my txt file is attached below please help me solve this

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Steve Eddins 2020-9-23

在 MATLAB Online 中打开

I can't figure out how the numbers in chalitp.txt correspond to the graph you are trying to make. Can you clarify what the numbers in the file mean? Which numbers are supposed to the surface height?

>> load chalitp.txt
>> chalitp
chalitp =
0000   90.0000  106.7730    0.9351    0.8177
0000   90.0000   99.4950    0.8714    0.6616
7356  -45.0000   97.6599    0.8553    0.6257
0000   45.0000   97.3437    0.8525    0.6196
9052   63.4349   99.3358    0.8700    0.6584
2394  -45.0000  101.6240    0.8900    0.7050
2394   45.0000  102.7843    0.9002    0.7294
0000   45.0000  102.8373    0.9006    0.7306
9052   26.5651  111.1650    0.9736    0.9228
4218  -45.0000  114.1827    1.0000    1.0000

Nagendra Kamath 2020-9-23

first column is theta

second one is phi

third is Ds

I wanted plot of theta vs phi vs Ds

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Answer 1

Ameer Hamza 2020-9-23

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https://ww2.mathworks.cn/matlabcentral/answers/598591-how-to-plot-3d-using-a-txt-file#answer_499186

在 MATLAB Online 中打开

I assume that first 3 columns are x, y, and z values. You need to use scatteredInterpolant

data = readmatrix('chalitp.txt');
x = data(:,1);
y = data(:,2);
z = data(:,3);
f = scatteredInterpolant(x, y, z);
xg = linspace(min(x), max(x), 20);
yg = linspace(min(y), max(y), 20);
[Xg, Yg] = meshgrid(xg, yg);
Zg = f(Xg, Yg);
surf(Xg, Yg, Zg);