def squareMean3( array, centerPixel ):
    """
    Kernel neighborhood function for focal map algebra. Reutrns mean of a 3x3 square array.
    @param array - array from which to retrieve the neighborhood kernel
    @param centerPixel - (i,j) corrdinates of center pixel of kernel in the array
    @return - mean of 3x3 square neighborhood around centerPixel
    """
    rows = centerPixel[0] - 1
    cols = centerPixel[1] - 1
    neighArray = array[rows:rows + 3, cols:cols + 3]
    return neighArray.mean()