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#1
July 14th, 2012, 09:36 PM
 cannes_major
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My first attempt at Python coding

I discovered Telit's line of GSM/GPS modules that have a built in Python interpreter. This peaked my curiousity so I decided to learn Python. Below is my first attempt at coding. I'm sure it looks sloppy but it works. It takes a list of GPS RMC sentences (to simulate a GPS serial input stream) and compares the "current position" with a list of geofences and reports the results (i.e. "300SD is at home", or "300SD is leaving home. Heading 309.62 degrees", etc.) It also reports stops and when the car is traveling over a predefined speed. Here's the code, comments welcome (remember, this is my very first attempt at programming!):

Code:
```#!/usr/local/bin/python
#monitors the current position of the gps unit and reports when the unit
#enters/exits predefined geofences ("zones")

import math
import time
import re    #used for the stopTimer functionality

tracklog = []
fences = []
rmclist = ["\$GPRMC,161229.000,A,3857.9760,N,07723.4240,W,0.13,309.62,121111,,*10",
"\$GPRMC,161431.000,A,3857.9810,N,07723.3390,W,20.1,309.62,121111,,*10",
"\$GPRMC,161633.000,A,3858.1200,N,07723.2700,W,21.5,309.62,121111,,*10",
"\$GPRMC,161835.000,A,3858.1280,N,07723.1740,W,24.4,309.62,121111,,*10",
"\$GPRMC,161936.000,A,3858.8400,N,07723.0340,W,24.4,309.62,121111,,*10",
"\$GPRMC,162037.000,A,3857.8420,N,07723.0370,W,0.00,309.62,121111,,*10",
"\$GPRMC,162637.000,A,3857.8420,N,07723.0370,W,0.00,309.62,121111,,*10",
"\$GPRMC,162739.000,A,3857.8620,N,07722.9940,W,14.8,309.62,121111,,*10",
"\$GPRMC,162941.000,A,3857.7420,N,07722.9080,W,27.0,309.62,121111,,*10",
"\$GPRMC,163343.000,A,3857.6500,N,07722.7390,W,32.8,309.62,121111,,*10",
"\$GPRMC,163545.000,A,3857.5360,N,07722.4720,W,38.3,309.62,121111,,*10",
"\$GPRMC,163747.000,A,3857.4420,N,07722.2770,W,37.8,309.62,121111,,*10",
"\$GPRMC,163949.000,A,3857.2840,N,07722.0840,W,0.00,309.62,121111,,*10",
"\$GPRMC,164151.000,A,3857.2330,N,07721.7880,W,18.6,309.62,121111,,*10",
"\$GPRMC,164353.000,A,3857.2500,N,07721.5490,W,27.5,309.62,121111,,*10",
"\$GPRMC,164555.000,A,3857.2720,N,07721.5530,W,0.00,309.62,121111,,*10",
"\$GPRMC,164757.000,A,3857.3420,N,07721.5540,W,0.18,309.62,121111,,*10"]
rlat = 0.0
rlon = 0.0
stat = ""
stopCounter = 0
notifyFlag = 0

data = open("fences.txt")
for each_line in data:
(name, lat, lon, boundary) = each_line.split(",")
lat = float(float(lat)/57.29577951)
lon = float(float(lon)/57.29577951)
boundary = float(boundary)
fence = (name, lat, lon, boundary)
fences.append(fence)
data.close

def gps():
#formats and parses incoming gps sentences
global ctime, rlat, rlon, lat, lon, speed, bearing, tracklog
nmea = rmclist.pop(0)
(header, utm, status, lat, NS, lon, EW, speed, bearing, date, magvar, checksum) = nmea.split(",")
ctime = utm[:2]+":"+ utm[2:4] + ":" + utm[4:6]
latd = int(lat[:2])
latm = float(lat[2:9])
lond = int(lon[:3])
lonm = float(lon[3:10])
lat = round((latd + latm/60), 4)
lon = round((lond + lonm/60), 4)
#rlon = float(lon/57.29577951)
speed = int(float(speed)*1.15077945)
new_entry = (ctime, lat, lon)
tracklog.append(new_entry)
return rlat, rlon, ctime, lat, lon, speed, bearing

def status():
#get current position and compare it with all geofences, reporting results
global stat, notifyFlag
for fence in fences:
name = fence[0]
glat = fence[1]
glon = fence[2]
boundary = fence[3]
x = (glon-rlon)*math.cos((glat+rlat)/2)
y = (glat-rlat)
d = math.sqrt(x*x+y*y) * 3958.756
if d < boundary:
stat = name
notifyFlag += 1
break
elif stat == name and d > boundary:
stat = "leaving", name
notifyFlag = 0
break
else:
stat = "roaming"
if stat == name and notifyFlag < 2:
print "\n", ctime, "300SD is at", name
elif stat == ("leaving", name):
print "\n", ctime + " 300SD is leaving", name + "; traveling at", speed, "mph; heading", bearing, "degrees"

for i in range(len(rmclist)):
gps()
status()
if speed > 35:
print "\n", ctime, "300SD is speeding! Currently travelling at", speed, "mph"
if speed != 0:
stopCounter = 0
if speed == 0 and stopCounter == 0:
stopCounter += 1
stopTimer = int(re.sub("\D", "", ctime))
startTime = stopTimer
if speed == 0 and stopCounter != 0 and (stopTimer - startTime) > 510:
print "\n", ctime, "300SD has stopped at", lat, "N", lon, "W"
time.sleep(2)```

#2
July 14th, 2012, 09:38 PM
 cannes_major
Registered User

Join Date: Jul 2012
Posts: 2
Time spent in forums: 30 m 3 sec
Reputation Power: 0
plans for version 2

I forgot to mention that in the next version I'm going to attempt to modularize the program.

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