Generate an equation from x,y and z data in a table/surface plot

Hi,

I wonder if there is any approach to generate a function for values on z based on x and y values, e.g. a X of 1 and a y of 4 corresponds to a z of 10. I know that this will depend on the behaviour of the function but is there a general approach to perform this in Matlab.

How I create the surface plot is according below:

z=Data(2:end,2:end)
z=table2array(z)

x=1:size(z,2)
y=1:size(z,1)

figure(1)
surf(x,y,z)

Thanks in advance.

Kind regards..

[Akira Agata]

If you don't need to fit a specific function, you can simply use 2D interpolation, like interp2.

[KSSV]

Attach your data.

[Vlatko Milic]

Please see the attached file

[Vlatko Milic]

@Akira Agata, I attach the file here. I tried with interp2 but could not make it work. I just want to specify the function for the data

Answer 1

[VINAYAK LUHA]

Hi Vlatko,

It is my understanding that you are looking to create an equation that relates the values of vector "z" to the corresponding values of vector "x" and "y”.

Following are the ways to devise an equation for “z” using “x” and “y” variables:

• Regression:

If you have a set of data points and want to fit a function to them, you can use regression techniques. Refer to the following documentation for fitting a polynomial function to a set of points-https://www.mathworks.com/help/matlab/ref/polyfit.html

• Interpolation:

If you have a set of discrete data points (x, y, z), you can use interpolation techniques to generate a continuous function. Refer to the following documentation for interpolating using “interp2” function- https://www.mathworks.com/help/matlab/ref/interp2.html

Hope this helps in devising an equation for “z” using “x” and “y” variables.

Regards,

Vinayak Luha