smart-gpx-merge

Merge multiple overlapping GPX files into a single continuous route — no straight lines, no duplicates.

Most GPX merge approaches draw straight lines between disconnected segments. smart-gpx-merge bridges gaps by retracing existing trail, producing a clean map you can load in offline GPX apps or print with topo contour lines.

Built for combining trail running / hiking GPS tracks from the same area (e.g., a mountain with many trails) into one unified map.

Features

• Duplicate removal — detects overlapping trail segments using spatial proximity and keeps only unique coverage
• Straight-line artifact removal — splits segments where GPS jumped (large gaps between consecutive points)
• Gap bridging — connects disjoint segments by retracing existing trail instead of drawing straight lines
• Downsampling — reduces point density from high-frequency GPS recordings while preserving trail shape
• Zero dependencies — pure Python 3, uses only the standard library

How It Works

Input: Multiple GPX files with overlapping routes
                    │
     1. Parse all track segments from all files
     2. Split segments at GPS jumps (straight-line artifacts)
     3. Downsample dense GPS recordings
     4. Deduplicate — keep segments that add new trail coverage
     5. Build a trail graph with junction connections
     6. Order segments to minimize gaps
     7. Bridge gaps via shortest path through existing trail
                    │
Output: One continuous GPX track covering all unique routes

Installation

# Using uv (recommended)
uv tool install smart-gpx-merge    # from PyPI
uv tool install .                   # from source

# Using pip
pip install smart-gpx-merge        # from PyPI
pip install .                       # from source

# Or run directly without installing
python3 smart_gpx_merge.py [args]

Usage

# Merge all .gpx files in a directory
smart-gpx-merge ./my_tracks/

# Merge specific files
smart-gpx-merge track1.gpx track2.gpx track3.gpx

# Custom output file and track name
smart-gpx-merge *.gpx -o merged.gpx --name "My Trail Map"

# Tune thresholds
smart-gpx-merge *.gpx --dup-radius 20 --gap-threshold 150

# Crop to a specific area and drop isolated segments
smart-gpx-merge *.gpx --bbox 10.505,107.10,10.56,107.155 --drop-isolated

Options

Example

Merging 4 GPX files with overlapping trail runs on the same mountain:

smart-gpx-merge ./tracks/ -o merged.gpx --name "Mountain Trails"

📂 route_a.gpx:          1 segment, 58,000 points
📂 route_b.gpx:          1 segment, 10,000 points
📂 route_c.gpx:          1 segment, 16,000 points
📂 previous_merged.gpx:  7 segments,  3,800 points

→ Deduplicated to 4 unique segments (6 discarded)
→ Bridged 2 gaps via existing trail
→ Output: 1 continuous track, ~7,200 points

Tips

• Duplicate radius (--dup-radius): Increase if parallel trails are being kept as separate segments. Decrease if distinct nearby trails are being merged incorrectly.
• Gap threshold (--gap-threshold): Lower this if you see GPS jumps that aren't being caught. Raise if legitimate trail sections are being split.
• Junction radius (--junction-radius): Controls how far apart two points from different segments can be and still be considered the same trail junction. Affects gap bridging quality.

Use with AI Agents

Option A: Claude Code Skill (no install needed)

Copy the skills/merge-gpx folder into your Claude Code skills directory:

mkdir -p ~/.claude/skills
cp -r skills/merge-gpx ~/.claude/skills/merge-gpx

Then use /merge-gpx in Claude Code. The skill bundles the Python script — no pip install required.

Option B: Any AI Agent

Install the CLI tool:

pip install smart-gpx-merge

Then add the following to your agent's instruction file (CLAUDE.md, AGENTS.md, .cursorrules, etc.):

## GPX Merge Tool

`smart-gpx-merge` is installed as a CLI tool for merging multiple GPX files.

Usage: smart-gpx-merge <inputs> [options]

Key flags:
- `-o, --output` — output file (default: merged_all_routes.gpx)
- `--dup-radius` — dedup radius in meters (default: 15)
- `--gap-threshold` — max gap before splitting (default: 100)
- `--bbox south,west,north,east` — crop to area
- `--drop-isolated` — remove unbridgeable segments
- `--name` — track name in output

Examples:
  smart-gpx-merge ./tracks/ -o merged.gpx
  smart-gpx-merge *.gpx --bbox 10.5,107.1,10.55,107.15 --drop-isolated

Works with any AI agent that has shell access (Claude Code, Cursor, Windsurf, Cline, etc.).

Requirements

• Python 3.8+
• No external dependencies

Acknowledgements

Built with Claude Code by Anthropic.

License

MIT