def _UTMLetterDesignator(Lat):
	"""This routine determines the correct UTM letter designator for the given latitude
	returns 'Z' if latitude is outside the UTM limits of 84N to 80S
	Written by Chuck Gantz- chuck.gantz@globalstar.com"""

	if 84 >= Lat >= 72: return 'X'
	elif 72 > Lat >= 64: return 'W'
	elif 64 > Lat >= 56: return 'V'
	elif 56 > Lat >= 48: return 'U'
	elif 48 > Lat >= 40: return 'T'
	elif 40 > Lat >= 32: return 'S'
	elif 32 > Lat >= 24: return 'R'
	elif 24 > Lat >= 16: return 'Q'
	elif 16 > Lat >= 8: return 'P'
	elif  8 > Lat >= 0: return 'N'
	elif  0 > Lat >= -8: return 'M'
	elif -8> Lat >= -16: return 'L'
	elif -16 > Lat >= -24: return 'K'
	elif -24 > Lat >= -32: return 'J'
	elif -32 > Lat >= -40: return 'H'
	elif -40 > Lat >= -48: return 'G'
	elif -48 > Lat >= -56: return 'F'
	elif -56 > Lat >= -64: return 'E'
	elif -64 > Lat >= -72: return 'D'
	elif -72 > Lat >= -80: return 'C'
	else: return 'Z'	# if the Latitude is outside the UTM limits