GPXScaler

GPXScaler is a Python tool designed to scale GPX route files both in distance and elevation (ascent/descent), while also allowing you to set a new starting coordinate for the routes.

Features

• Scale Distance: Modify the horizontal distance of routes by a specified factor
• Scale Elevation: Adjust ascent and descent values by the same scaling factor
• Relocate Routes: Set new starting coordinates for your routes
• Batch Processing: Process all GPX files in a specified folder
• Route Analysis: Display total distance and ascent for each route before scaling
• Auto-Location: Attempts to use device's current location as default starting point

Usage

Command Line Arguments

python gpxscaler.py [--folder FOLDER] [--scale FACTOR] [--min-distance DISTANCE] [--start-lat LATITUDE] [--start-lon LONGITUDE]

Arguments

• --folder: Target folder containing GPX files (default: current directory)
• --scale: Scaling factor for distance and elevation (e.g., 0.5 for half size, 2.0 for double)
• --min-distance: Minimum distance in km - scale will be automatically adjusted if the scaled route would be shorter than this
• --start-lat: New starting latitude coordinate
• --start-lon: New starting longitude coordinate

Interactive Mode

If no command line arguments are provided, the script will run in interactive mode:

1. Folder Selection: Choose the folder containing GPX files (defaults to current directory)
2. Route Analysis: View distance and elevation data for each GPX file
3. Scale Factor: Enter the desired scaling factor
4. Minimum Distance (optional): Set a minimum distance requirement - routes shorter than this will be automatically scaled up
5. Starting Coordinates: Set new starting coordinates (attempts to auto-detect current location)

Examples

# Scale all GPX files in current directory by 75% with minimum 50km distance and set new start point
python gpxscaler.py --scale 0.75 --min-distance 50 --start-lat 45.5088 --start-lon -73.5878

# Process GPX files in a specific folder with minimum distance requirement
python gpxscaler.py --folder "./tour-routes" --scale 1.2 --min-distance 40

# Interactive mode (no arguments)
python gpxscaler.py

Requirements

• Python 3.6+
• gpxpy library for GPX file parsing
• requests library for location services (optional)

Installation

1. Clone or download this repository

2. Install required dependencies:

   pip install gpxpy requests

Output

The scaled GPX files will be saved in a scaled subfolder (created automatically if it doesn't exist) with a suffix indicating the scaling factor, for example:

• stage-1-route.gpx → scaled/stage-1-route_scaled_075.gpx (for 0.75x scaling)

Notes

• Original GPX files are preserved; scaled versions are created as new files in the scaled subfolder
• The scaled subfolder is created automatically in the same directory as the source GPX files
• Elevation scaling applies proportionally to both ascent and descent
• The tool maintains the relative shape and characteristics of the original routes using vector-based scaling
• Location auto-detection requires an internet connection and may not work in all environments

Indoor Training Platforms

GPXScaler generates routes that work well with various indoor training simulators. Here are some recommended platforms that preserve elevation data:

Open Source Options

• Auuki - Open source indoor training simulator that preserves imported elevation data from GPX/TCX/FIT files
• GoldenCheetah - Open source cycling analysis platform with extensive GPX/TCX/FIT support

Commercial Platforms (Known to Preserve Elevation)

• Wahoo Fitness Platform - Confirmed to preserve elevation data in indoor training simulator

Note for Garmin Connect Users

Garmin Connect often auto-corrects elevation data, potentially overriding your scaled routes. Consider using TCX format (--tcx flag) or alternative platforms for better elevation preservation.

License

This project is open source. Feel free to modify and distribute as needed.