Subscript indices must either be real positive integers or logicals with interp2

Question

What does the error "Subscript indices must either be real positive integers or logicals" means when using interp2. X,Y,Z,XI,YI are all vectors of the same length.

Answer 1

It means that you trying to access an element in an array by using index as number with decimal point or a negative number, or maybe even using a string that looks like a number e.g. "2".

The only way to access the elements is by using positive integer OR logical (0 or 1).

array = [1 2 3 4 5 6];
array(4)    # returns 4th element of the array, 4.
mask = array > 3; # creates a mask of 0's and 1's (logicals).
array(mask) # return elements greater than 3, 4 5 6.

BUT you can't do:

array(2.0)

Or anything else other than positive integer or logical.

Alex