Calculate live distance between two GPS(NMEA) over TCP devices.

dist.py

#!/usr/bin/env python3

# Calculates distance between two GPS (NMEA) devices sharing location over TCP.
#
# Dependencies : pynmea2, arlpy
#
# Usage dist.py <local-ip-address> <local-gps-port> <remote-ip-address> <remote-gps-port>
# Usage dist.py <local-ip-address> <remote-ip-address>


import sys
import socket
import time
import threading
import datetime
from arlpy import geo
import pynmea2


local_gps_port = 7777
remote_gps_port = 7777

if len(sys.argv) < 3:
	print("Need atleast 2 IP addresses as arguments")
	exit(-1);

if len(sys.argv) == 4:
	print("Please indicate both GPS ports")
	exit(-1);

if len(sys.argv) == 5:
	remote_gps_port = int(sys.argv[4])
	local_gps_port = int(sys.argv[2])
	remote_ip = sys.argv[3]
	local_ip = sys.argv[1]
else :
	remote_ip = sys.argv[2]
	local_ip = sys.argv[1]

lat_local = 0
lon_local = 0
lat_remote = 0
lon_remote = 0

def print_dist():
	global lat_local, lat_remote, lon_local, lon_remote
	if (lat_local > 0 and lat_remote > 0 and lon_local > 0  and lon_remote > 0):
		time = datetime.datetime.now().strftime('%H:%M:%S')
		dist = geo.distance(geo.pos([lat_local, lon_local]), geo.pos([lat_remote, lon_remote]))
		print(str(time) + " , " + str(format(dist,'.2f')))

def local_connected(s):
	global lat_local, lat_remote, lon_local, lon_remote
	print("Connected to local.")
	for line in s.makefile('r'):
		if (line.startswith('$GPGGA')):
			try:
				msg = pynmea2.parse(line)
			except pynmea2.nmea.ParseError as e:
				continue;
			lat_local = msg.latitude
			lon_local = msg.longitude
			print_dist()


def local_recv_proc():
	while True:
		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
		try:
			s.connect((local_ip, local_gps_port));
			local_connected(s)
			s.close()
		except Exception as e:
			pass
		print("Disconnected to remote. Trying again.")
		time.sleep(1)

def remote_connected(s):
	global lat_local, lat_remote, lon_local, lon_remote
	print("Connected to remote.")
	for line in s.makefile('r'):
		if (line.startswith('$GPGGA')):
			try:
				msg = pynmea2.parse(line)
			except pynmea2.nmea.ParseError as e:
				continue;
			lat_remote = msg.latitude
			lon_remote = msg.longitude
			print_dist()

def remote_recv_proc():
	while True:
		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM);
		try:
			s.connect((remote_ip, remote_gps_port));
			remote_connected(s)
			s.close()
		except Exception as e:
			pass
		print("Disconnected to remote. Trying again.")
		time.sleep(1)


local_recv_thread = threading.Thread(target=local_recv_proc)
local_recv_thread.start()

remote_recv_thread = threading.Thread(target=remote_recv_proc())
remote_recv_thread.start()