parse GPX trackfiles

gistfile1.py

from xml.etree import ElementTree as et
import sys
from datetime import datetime

def _(tag):
    return '{%s}%s' % ('http://www.topografix.com/GPX/1/1', tag)

def parse(f):
    node = et.parse(f).getroot()
    for p in node.findall('.//%s' % _('trkpt')):
        lat = float(p.attrib['lat'])
        lon = float(p.attrib['lon'])
        alt = float(p.find(_('ele')).text)
        timestamp = datetime.strptime(p.find(_('time')).text, '%Y-%m-%dT%H:%M:%SZ')

        yield (timestamp, lat, lon, alt)


if __name__ == "__main__":

    with open(sys.argv[1]) as f:
        print sorted(list(parse(f)))