Read and parse NMEA data info from USB GPS dongle

nmea.py

#!/usr/bin/python
import re
from decimal import Decimal
import math
import time
import serial

class FormatNMEA(object):

	@staticmethod
	def format(string):
		'''
		Format string default NMEA GGA
		'''
		arr = []
		arr = string.split(',')
		if(arr.__len__() >= 9):
			''' expected format ''' 
			try:
				lat = float( arr[2][2:arr[2].__len__()] )
				latd = int( FormatNMEA.getLatDeg(arr[2]) )
				latway = arr[3] # S = (-)

				lng = float( arr[4][3:arr[4].__len__()] )
				lngd = int( FormatNMEA.getLngDeg(arr[4]) )
				lngway = arr[5] # W = (-)

				#print FormatNMEA.calculeDecimal(latd, lat, latway)
				#print FormatNMEA.calculeDecimal(lngd, lng, lngway)				 
				return [FormatNMEA.calculeDecimal(latd, lat, latway), FormatNMEA.calculeDecimal(lngd, lng, lngway)]
			except (IndexError):
				return []

	@staticmethod
	def getLatDeg(lat):
		return lat[0:2]

	@staticmethod
	def getLngDeg(lng):
		return lng[1:3]

	@staticmethod
	def calculeDecimal(deg_part, min_part, way):
		if(way == 'S' or way == 'W'): 
			way = "-"
		else:
			way = ""
		return way + str(deg_part + (min_part / 60))
  
# Start serial coon
comport = serial.Serial('/dev/ttyUSB1', 4800)
comport.timeout = 1

while True:
  data = comport.readline()
  if data[0:6] == '$GPGGA':
    coords = FormatNMEA.format(data)
    print coords

comport.close()