Randomize GPX trajectory in space and time

generate-commute-tracks.py

#!/usr/bin/python
# TODO: port to Python3
# Take an input GPX track and generate a series of identical tracks
# shifted in time and with noise added to individual points' coordinates and
# timestamps.

import xml.etree.ElementTree as ET

from sys import argv
from random import random
from datetime import datetime
from datetime import timedelta
from dateutil import parser as date_parser
from dateutil.rrule import DAILY, rrule, MO, TU, WE, TH, FR

def daterange(start_date, end_date):
    # return only working days in the region
    # I did not work much on Fridays, so exclude it
    return rrule(DAILY, dtstart=start_date, until=end_date, byweekday=(MO,TU,WE,TH)) # FR

def get_noise(percentage = 0.5):
    return 1.0 + (random() - 0.5) * percentage / 100.0

# TODO only the last register_namespace takes effect?
ET.register_namespace('', "http://www.topografix.com/GPX/1/1")
ET.register_namespace('', "http://www.topografix.com/GPX/1/0")
ET.register_namespace("xsi", "http://www.w3.org/2001/XMLSchema-instance")

et = ET.parse(argv[1])
root = et.getroot()

script = open("batch-upload.sh", "w")

script.write("#!/bin/sh\n")
script.write("set -e\n")

# morning track
start_date = datetime(2019, 2, 1, 8, 00, 00)
end_date   = datetime(2019, 8, 20, 8, 45, 00)

# evening track
#start_date = datetime(2018, 2, 1, 16, 30, 00)
#end_date   = datetime(2019, 8, 20, 16, 45, 00)

for new_date in daterange(start_date, end_date):
    global_time_shift = (random() - 0.5) * 3600 # plus minus half hour
    first_time = None

    for item in root.iter():
        if item.tag.find("name") != -1:
            item.text = "Commute " + new_date.isoformat()
            print "Working with", item.text

        if item.tag.find("trkpt") != -1: # tag contains stupid namespace prefix
            lat = float(item.attrib['lat'])
            lon = float(item.attrib['lon'])
            lat *= get_noise(0.0001)
            lon *= get_noise(0.0001)
            item.attrib['lat'] = str(lat)
            item.attrib['lon'] = str(lon)

        if item.tag.find("ele") != -1:
            ele = float(item.text)
            ele *= get_noise(5.0)
            item.text = str(ele)
        if item.tag.find("time") != -1:
            old_time = date_parser.parse(item.text)
            if first_time is None:
                first_time = old_time

            path_delta = old_time - first_time

            local_shift = (random() - 0.5) * 0.05
            noise_delta = (timedelta(seconds=global_time_shift) +
                           timedelta(seconds=local_shift))

            new_time = new_date + path_delta + noise_delta
            item.text = new_time.isoformat()

    # Write back to file
    newfname = "commute-" + new_date.strftime("%s") + ".gpx"
    et.write(newfname)
    script.write("~/workspace/stravacli/stravaup.py --no-popup --xml-desc --activity-type ride %s\n" % (newfname))
    script.write("sleep 3\n")

script.close()