def min (field,axis=None): 
        import numpy as np
        return np.array(field).min(axis=axis)

def max (field,axis=None):
        import numpy as np
        return np.array(field).max(axis=axis)

def mean (field,axis=None):
        import numpy as np
        return np.array(field).mean(axis=axis)

def deg ():
        return u'\u00b0'