__init__(self, x, y, z, kind = 'linear', copy = True, bounds_error = False, fill_value = None)
Input:
x,y - 1-d arrays defining 2-d grid (or 2-d meshgrid arrays)
z - 2-d array of grid values
kind - interpolation type ('linear', 'cubic', 'quintic')
copy - if true then data is copied into class, otherwise only a
reference is held.
bounds_error - if true, then when out_of_bounds occurs, an error is
raised otherwise, the output is filled with
fill_value.
fill_value - if None, then NaN, otherwise the value to fill in
outside defined region.