My first attempt at Python coding

#!/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)
    rlat,rlon = map(math.radians, [lat, lon])
    #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)