gpx-interpolate.py

Python script to interpolate GPX files using piecewise cubic Hermite splines.

Interpolates latitude, longitude, elevation and speed at any spatial resolution.

User command line options:

define total number of the new interpolated track points ; or
define track points in constant distance steps

Optionally you can define

constant speed (e. g. 1 m/s); or
constant time intervals between track points (e.g. define a point every second)
set (or overwrite existing) start track time (optional) e.g 20240201-120000Z

Output shows

start and end time based on input parameters
total track length
total track travel time based on the given speed or time interval data

Usage

Script

usage: gpx-interpolate.py [-h] [-d DISTANCE] [-n NUM] [-i INTERVALTIME] [-v VELOCITY] [-s] [-b BEGINTIME] FILE [FILE ...]

interpolate GPX files using piecewise cubic Hermite splines

positional arguments:
  FILE                  GPX file

options:
  -h, --help            show this help message and exit
  -d DISTANCE, --distance DISTANCE
                        set constant distance (interpolation resolution) between track points [m] (default: 1 m)
  -n NUM, --num NUM     force number of track points (default: disabled)
  -i INTERVALTIME, --intervaltime INTERVALTIME
                        set constant time interval [s] between track points
  -v VELOCITY, --velocity VELOCITY
                        set constant velocity [m/s] between track points
  -s, --speed           add speed data to track
  -b BEGINTIME, --begintime BEGINTIME
                        set track begin time UTC [YYYYMMDD-HHMMSSZ]

Module

from gpx-interpolate import gpx_interpolate

gpx_data = {'lat':lat,
            'lon':lon,
            'ele':ele,
            'tstamp':tstamp,
            'tzinfo':tzinfo}

gpx_data_interp = gpx_interpolate(gpx_data, distance=1.0)

where:

lat, lon are the trackpoints latitude and longitude (in degree)
ele (optional) is the trackpoints elevation (in meter)
tstamp (optional) is the trackpoints timestamps (in second)
tzinfo (optional) is the trackpoints timezone as a datetime.tzinfo subclass instance (None for UTC)
distance is the interpolation resolution in meters (1.0 by default, disabled if num is passed)
num (optional) is the number of trackpoints of the interpolated data (None by default)

ele, tstamp and tzinfo are optional and can be set to None.

Example

🔴 input GPX data (6 points) 🟢 interpolated GPX data every 50 km (d=50000) 🔵 interpolated GPX data 10 points (n=10)

Test

Run ./test.sh

Requirements

gpxpy==1.5.0
scipy==1.8.0
numpy==1.22.2