gpsfix.py   [plain text]

#!/usr/bin/env python
"""
GPSTest is a simple example using the SerialPort transport and the NMEA 0183 and Rockwell Zodiac GPS protocols to display fix data as it is received from the device.
"""
from twisted.python import log, usage
import sys

if sys.platform == 'win32':
    # win32 serial does not work yet!
    raise NotImplementedError, "The SerialPort transport does not currently support Win32"
    from twisted.internet import win32eventreactor
    win32eventreactor.install()

class GPSFixLogger:
    def handle_fix(self, *args):
      """handle_fix gets called whenever either rockwell.Zodiac or nmea.NMEAReceiver receives
      and decodes fix data.  Generally, GPS receivers will report a fix at 1hz.  
      Implementing only this method is sufficient for most purposes unless tracking of ground speed,
      course, utc date, or detailed satellite information is necessary.

      For example, plotting a map from MapQuest or a similar service only requires longitude and latitude.
      """
      log.msg('fix:\n' + 
      '\n'.join(map(lambda n: '  %s = %s' % tuple(n), zip(('utc', 'lon', 'lat', 'fix', 'sat', 'hdp', 'alt', 'geo', 'dgp'), map(repr, args)))))

class GPSOptions(usage.Options):
    optFlags = [
        ['zodiac', 'z', 'Use Rockwell Zodiac (DeLorme Earthmate) [default: NMEA 0183]'],
    ]
    optParameters = [
        ['outfile', 'o', None, 'Logfile [default: sys.stdout]'],
        ['baudrate', 'b', None, 'Serial baudrate [default: 4800 for NMEA, 9600 for Zodiac]'],
        ['port', 'p', '/dev/ttyS0', 'Serial Port device'],
    ]


if __name__ == '__main__':
    from twisted.internet import reactor
    from twisted.internet.serialport import SerialPort

    o = GPSOptions()
    try:
        o.parseOptions()
    except usage.UsageError, errortext:
        print '%s: %s' % (sys.argv[0], errortext)
        print '%s: Try --help for usage details.' % (sys.argv[0])
        raise SystemExit, 1

    logFile = o.opts['outfile']
    if logFile is None:
        logFile = sys.stdout
    log.startLogging(logFile)

    if o.opts['zodiac']:
        from twisted.protocols.gps.rockwell import Zodiac as GPSProtocolBase
        baudrate = 9600
    else:
        from twisted.protocols.gps.nmea import NMEAReceiver as GPSProtocolBase
        baudrate = 4800
    class GPSTest(GPSProtocolBase, GPSFixLogger):
        pass
    
    if o.opts['baudrate']:
        baudrate = int(o.opts['baudrate'])


    port = o.opts['port']
    log.msg('Attempting to open %s at %dbps as a %s device' % (port, baudrate, GPSProtocolBase.__name__))
    s = SerialPort(GPSTest(), o.opts['port'], reactor, baudrate=baudrate)
    reactor.run()