Mockup point time with gpxpy

title says all

PublishedFebruary 4, 2025

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HU, Pili

Just run the code, or yourself.

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Introduction

The scenario:

Some GPX files are painted using software and does not have valid timestamp.

Having timestamp is required by GPX standard (Ref: Decode the Chong Li 168 GPX files error ), but not fully respected by many modern software/ hardwares.

You may need valid timestamp to upload an activity onto Strava.

The solution:

In the basic mode, we start from a preset time and increment the time for each point in chronological order.

In the advanced mode, we start from a user defined time and calculate elapsed time between points according to the designated speed.

The Code

''' Usage: gpx_mockup_time.py <input_gpx> <output_gpx> gpx_mockup_time.py <input_gpx> <output_gpx> <mockup_time_start> <mockup_speed_meters_per_second> <track_name> Options: -h help -v version ''' # Example usage: # %python gpx_mockup_time.py compare-hk100/2025HK100.gpx compare-hk100/hk100-mockup.gpx '2025-01-01 08:08:01 +08:00' 1.38 'HK100 mockup' import docopt import logging import gpxpy import gpxpy.gpx from gpxpy import geo from datetime import timedelta from dateutil import parser as dt_parser from gpxpy import geo DEFAULT_START_TIME_BASIC_MODE = dt_parser.parse('9999-12-15 0:0:1 +08:00') def mockup_time_basic(reverse=False): if not hasattr(mockup_time_basic, '_last_mockup_time'): mockup_time_basic._last_mockup_time = DEFAULT_START_TIME_BASIC_MODE if reverse: mockup_time_basic._last_mockup_time -= timedelta(seconds=1) else: mockup_time_basic._last_mockup_time += timedelta(seconds=1) return mockup_time_basic._last_mockup_time if __name__ == "__main__": logging.getLogger().setLevel(logging.INFO) arguments = docopt.docopt(__doc__) gpx_file = open(arguments['<input_gpx>'], 'r') gpx = gpxpy.parse(gpx_file) print('Finished loading GPX') print(gpx) mockup_time_start = arguments['<mockup_time_start>'] mockup_speed_meters_per_second = arguments['<mockup_speed_meters_per_second>'] track_name = arguments['<track_name>'] if mockup_time_start and mockup_speed_meters_per_second: # Advanced mode mockup_speed_meters_per_second = float(mockup_speed_meters_per_second) print('[Advanced] Processing mockup time.') cur_time = dt_parser.parse(mockup_time_start) gpx.name = track_name last_point = None for track in gpx.tracks: track.name = track_name for segment in track.segments: for point in segment.points: if last_point is None: pass else: dist = geo.haversine_distance(point.latitude, point.longitude, last_point.latitude, last_point.longitude) delta_time = timedelta(seconds=(dist / mockup_speed_meters_per_second)) cur_time += delta_time # print(delta_time) point.time = cur_time last_point = point else: # Basic mode print('[Basic] Processing mockup time.') gpx.time = DEFAULT_START_TIME_BASIC_MODE for track in gpx.tracks: track.name = track_name for segment in track.segments: for point in segment.points: point.time = mockup_time_basic() c = open(arguments['<output_gpx>'], 'w').write(gpx.to_xml()) print(f'Write {c} chars to new GPX {arguments["<output_gpx>"]}')

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Introduction

The Code