Extract value from a 3D array with interpolation

I have a 3D array with row (row_ID), column (col_ID) and Z (z_ID) identifiers.

Essentially what I need is:

1. For a particular (row_ID, col_ID, z_ID), return the data value stored at that location.
2. If the (row_ID, col_ID) are not integers, then perform an interpolated value. z_ID will always be an integer.

Thank you

Answer 1

[KSSV]

load data.mat ;
A = gim_tec ;
[m,n,p] = size(A) ;
x = 1:n ;
y = 1:m ;
[X,Y] = meshgrid(x,y) ;
%%pick series if integer 
row = 2 ;
col = 3 ;
iwant = zeros(1,p) ;
for i = 1:p
    iwant(i) = A(row,col,i) ;
end
%%If fractions 
row = 1.5 ;
col = 7.5 ;
iwant1 = zeros(1,p) ;
for i = 1:p
    iwant1(i) = interp2(X,Y,A(:,:,i),row,col) ;
end

[BenL]

Hi KSSV

Thank you for the response, how do I input the desired row, column and Z values? Do i edit the row= and col= ? What about the Z value?

[KSSV]

Yes row and col is your desired row_ID, col_ID and z value is what you find i.e iwant.

[BenL]

where do I input the 3rd dimension? say if I want to return the value stored at row_ID = 20, col_ID = 30, Z = 12 (i.e. 20,30,12)?

[KSSV]

This gives only one output.....A(20,30,12).

Third dimension is the one you seek/ find for given row_id and col_id. For a given id's you will get respective z values which are 25 in number.

[BenL]

Oh i see! Just wondering, is it possible to interpolate using a surface instead of a linear interpolation scheme?

[Walter Roberson]

griddedInterpolant()

[KSSV]

interp2 is not linear ...Read documentation...As suggested by Walter have a look into griddedInterpolant.

[Walter Roberson]

interp2 defaults to linear, but there are some options