How to transfer surf(x,y,z) to a data contains height value?

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Yu Zou 2018-1-18

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/377825-how-to-transfer-surf-x-y-z-to-a-data-contains-height-value

回答： Walter Roberson 2018-1-19

在 MATLAB Online 中打开

Greeting everyone!

What i have now is 3 Matrix x,y,z, which can be presented by surf(x,y,z).

But i want to transfer these data to one matrix containing height value, which can be presented by surf(f).

Thanks!

Here is my data:

[x,y,z] = sphere;      % Makes a 21-by-21 point sphere
x = x(11:end,:);       % Keep top 11 x points
y = y(11:end,:);       % Keep top 11 y points
z = z(11:end,:);       % Keep top 11 z points
r = 3;                 % r radius value
x=r*x+r;
y=r*y+r;               % Move x, y starting from 0
z=r*z;                 % Change the radius of the dom to r
% so i generate a dom(half ball) with radius 3

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Walter Roberson 2018-1-18

surf(f) is the same as surf(1:size(f,1), 1:size(f,2), f) so the only way to get this to work would be to interpolate or extrapolate values at unit intervals so that the tick labels line up with the data values.

This would not seem to be a useful thing to do. If you have the coordinates of the data points available, then use them.

Yu Zou 2018-1-19

thanks for advice. I want to extract the height from a dom so that i can execute something else, so it's pretty useful for me.

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Answer 1

Image Analyst 2018-1-18

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https://ww2.mathworks.cn/matlabcentral/answers/377825-how-to-transfer-surf-x-y-z-to-a-data-contains-height-value#answer_300755

Try interp2() to take your coordinates and make a 2-D matrix where the values are the z values.

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Image Analyst 2018-1-19

Not sure since I don't have any data to try. You forgot to attach your data. Make it easy for people to help you, not hard, by attaching your data.

Yu Zou 2018-1-19

Thanks for advice, i've attached my code

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Answer 2

Walter Roberson 2018-1-19

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/377825-how-to-transfer-surf-x-y-z-to-a-data-contains-height-value#answer_300930

在 MATLAB Online 中打开

F = scatteredInterpolant(x(:),y(:),z(:));
[X,Y] = ndgrid(1:floor(max(x(:))));
Z = F(X,Y);
surf(Z)

You will find this rather unsatisfactory, but it is the best that can be done while maintaining the axes labels with a simple surf(Z)

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