Write GPS data to a file using Python and GPSd

gpsDataWrite.py

# Runs perfectly using Python 2.7.3 on Raspian.		
# GPSD Official Documentation: 					  
# http://www.catb.org/gpsd/gpsd_json.html			

# Original GpsPoller script by Dan Mandle: 						  
# http://www.danmandle.com/blog/getting-gpsd-to-work-with-python/ 
# Original readCoordinates funtion by recantha:				      
# https://github.com/recantha/picorder-v3/blob/master/picorder.py 
# Additional modifications by Jacob Ilkka:						  
# http://blog.jacobilkka.com/python-gps-data-writer/
# https://gist.github.com/jilkka/c4d0d384ea659022e857046bbe0a5739



import os
import time
import math
import threading
from gps import *

gpsd = None #seting the global variable

class GpsPoller(threading.Thread):
	def __init__(self):
		threading.Thread.__init__(self)
		global gpsd #bring it in scope
		gpsd = gps(mode=WATCH_ENABLE) #starting the stream of info
		self.current_value = None
		self.running = True #setting the thread running to true

	def run(self):
		global gpsd
		while gpsp.running:
			gpsd.next() #this will continue to loop and grab EACH set of gpsd info to clear the buffer
 
if __name__ == '__main__':
	gpsp = GpsPoller() # create the thread
	try:
		gpsp.start() # start it up
		while True:

			def readCoordinates():
				lat = gpsd.fix.latitude
				lon = gpsd.fix.longitude
				speed = float("{0:.2f}".format(gpsd.fix.speed / .44704)) # convert to mph
				alt = float("{0:.2f}".format(gpsd.fix.altitude / .3048)) # convert to feet
				climb = float("{0:.2f}".format(gpsd.fix.climb / .3048))  # convert to ft/s
				track = gpsd.fix.track
				fixtype = gpsd.fix.mode

				if (math.isnan(lat)):
					lat = "No fix"

				if (math.isnan(lon)):
					lon = "No fix"

				if (math.isnan(speed)):
					speed = "No fix"
				else:
					speed = "%s mph" % speed

				if (math.isnan(alt)):
					alt = "No fix"
				else:
					alt = "%s ft" % alt

				if (math.isnan(climb)):
					climb = "N/A"
				else:
					climb = "%s ft/s" % climb

				if (math.isnan(track)):
					track = "%s'" % track
				else:
					track = "No Track"

				if fixtype == 1:
					fixtype = "No Fix"
				else:
					fixtype = "%sD" % fixtype

				coords = [lat, lon, alt, speed, climb, track, fixtype]

				return coords

			coords = readCoordinates()
			d = open('currentData.py', 'w')
			d.write('# currentData.py \n \ncoords = %s' % coords)
			d.close()

			print "\n \n"
				
			latitude = coords[0]
			longitude = coords[1]
			altitude = coords[2]
			heading = coords[5]
			speed = coords[3]
			climb = coords[4]
			fi = coords[6]

			print "Latitude:  ", latitude
			print "Longitude: ", longitude
			print "Elevation: ", altitude
			print "Heading:   ", heading
			print "Speed:     ", speed
			print "Climb:     ", climb
			print "Fix:       ", fi 

			time.sleep(10)
			
	except (KeyboardInterrupt, SystemExit): #when you press ctrl+c
		print "\nKilling Thread..."
		gpsp.running = False
		gpsp.join() # wait for the thread to finish what it's doing
	print "Done.\nExiting."