Combine Halfmile GPX segments into one or a few big GPX files

combine_halfmile_gpx.py

#! /usr/bin/env python3
"""
Program: Combine Halfmile GPX tracks into a single GPX track
Author:  Kyle Barron
"""

import io
import requests
import gpxpy
import gpxpy.gpx

from zipfile import ZipFile


def main():
    for state in ['ca1', 'ca2', 'or', 'wa']:
        gpxs = download_gpx_tracks(state[:2])
        tracks, waypoints = split_into_tracks_and_waypoints(gpxs)
        split = int(state[2]) if state.startswith('ca') else None
        tracks = combine(sort_gpxs(tracks), split)
        waypoints = combine(sort_gpxs(waypoints), split)

        with open(f'{state}_pct_tracks.gpx', 'w') as f:
            f.write(tracks.to_xml())
        with open(f'{state}_pct_waypoints.gpx', 'w') as f:
            f.write(waypoints.to_xml())


def download_gpx_tracks(state):
    headers = {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36'}
    unzipped_content = {}
    url = 'https://www.pctmap.net/wp-content/uploads/pct'
    url += f'/{state}_state_gps.zip'
    r = requests.get(url, headers=headers)
    content = io.BytesIO(r.content)
    with ZipFile(content) as zf:
        for name in zf.namelist():
            if not name.startswith(state):
                continue
            if not name.endswith('.gpx'):
                continue
            unzipped_content[name] = zf.read(name).decode('utf-8')

    return unzipped_content


def split_into_tracks_and_waypoints(gpxs):
    tracks = {}
    waypoints = {}
    for name, data in gpxs.items():
        if name.endswith('tracks.gpx'):
            tracks[name] = data
        elif name.endswith('waypoints.gpx'):
            waypoints[name] = data
        else:
            raise Exception()

    return tracks, waypoints


def sort_gpxs(gpx):
    return dict(sorted(gpx.items()))


def combine(gpx, split=None):
    new_gpx = gpxpy.gpx.GPX()

    if split is not None:
        if split == 1:
            gpx = dict(list(gpx.items())[:len(gpx) // 2])
        elif split == 2:
            gpx = dict(list(gpx.items())[len(gpx) // 2:])
        else:
            raise Exception('split must be 1, 2, or None')

    for name, g in gpx.items():
        g = gpxpy.parse(g)
        for track in g.tracks:
            new_gpx.tracks.append(track)
        for waypoint in g.waypoints:
            new_gpx.waypoints.append(waypoint)
        for route in g.routes:
            new_gpx.routes.append(route)

    return new_gpx

if __name__ == '__main__':
    main()