how to find y value from the 3d graph with a known x and z values

I have a question, and I hope you can answer it

I have plot 3d graph ( as i have attached in image 1 ) between

x=[2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3]

y=[3.5,6.9,17.7,29.1,35.2,3.5,6.8,17.5,28.7,34.8,3.4,6.6,16.9,27.6,33.5]

z=[450,450,450,450,450,350,350,350,350,350,250,250,250,250,250]

after that

I have 20 patient

and each patient have associated with different z , x and y values

and for each patient i have z and x values , but i dont have y

And I want to know y value for each patient

so that why i have collect data ( as you can see above )( and all this data i have collect it are in the range of my patient ) and i have plot a 3d graph to estimate the y for each patent from this data ( lookup table )

For example

Patient number 4

Z = 367

x = 20

Y = ???

As you can see from the 3d image i have attached ( image 2 and 3) I can estimate what is the y for patient 4, But it will be very difficult and not accurate

so I am looking for stander fit to estimate y for each z and x values I have for 20 patient

I am looking for a function to estimate y for each z and x values I have for 20 patient

Answer 1

[Guillaume]

Seems fairly simply, just build a scattered interpolant and use that to interpolate your query points.

x=[2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3];	
y=[3.5,6.9,17.7,29.1,35.2,3.5,6.8,17.5,28.7,34.8,3.4,6.6,16.9,27.6,33.5];
z=[450,450,450,450,450,350,350,350,350,350,250,250,250,250,250];

YfromXZ = scatteredInterpolant(x(:), z(:), y(:));  %interpolant that lets you calculate y knowing x and z

queryx = 20;    %can be a vector/matrix
queryz = 367;   %can be a vector/matrix as long as it's the same size as queryx
matchingy = YfromXZ(queryx, queryz);

%for visualisation
figure; scatter3(x, y, z); hold('on'); plot3(queryx, matchingy, queryz, 'r*');

[ahmad albngali]

this was very good

thank you for help

[ahmad albngali]

hi

after i have plot between x y and z

x=[2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3,2.6,5.2,14,23.3,28.3];

y=[3.5,6.9,17.7,29.1,35.2,3.5,6.8,17.5,28.7,34.8,3.4,6.6,16.9,27.6,33.5];

z=[450,450,450,450,450,350,350,350,350,350,250,250,250,250,250];

i want to make error bar for y in the same graph

and i have the stander division for y

which is ( 0.047140452, 0.047140452, 0.047140452, 0.124721913, 0.047140452, 0.047140452, 0.047140452, 0.047140452, 0.124721913, 0.124721913, 0.047140452, 0.047140452, 0.047140452, 0.124721913, 0.124721913)

so culd you tell me what is the code for that