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OSM to GNG Direct Converter

One-step converter: OpenStreetMap → GNG KML format

No intermediate files. Just query OSM and get GNG-ready output.

Quick Start

Single Airport

python osm_to_gng_direct.py CYHZ --name "Halifax" --fir CZQM

Creates: CYHZ_gng.kml ready for GNG import.

All CZQM/CZQX Airports

python batch_process.py

Processes all airports defined in the script:

  • CYHZ (Halifax)
  • CYYT (St Johns)
  • CYQM (Greater Moncton)
  • CYSJ (Saint John)
  • CYFC (Fredericton)

Output files in output/ directory.

Complete Workflow

OpenStreetMap
    ↓
[osm_to_gng_direct.py] ← ONE SCRIPT
    ↓
GNG KML (ready to import)
    ↓
[Google Earth Pro] - Optional review
    ↓
[GNG Import]
    ↓
[GNG Export to EuroScope]
    ↓
Done!

Command Reference

Basic Usage

python osm_to_gng_direct.py <ICAO> --name "<Airport Name>" [options]

Options

  • --name (required): Airport name for folder structure
  • --fir: FIR code (default: CZQM)
  • --output / -o: Output filename (default: <ICAO>_gng.kml)

Examples

# Halifax (CZQM)
python osm_to_gng_direct.py CYHZ --name "Halifax"

# St Johns (CZQX)
python osm_to_gng_direct.py CYYT --name "St Johns" --fir CZQX

# Custom output location
python osm_to_gng_direct.py CYQM --name "Greater Moncton" -o custom/moncton.kml

What It Does

  1. Queries OpenStreetMap via Overpass API for:

    • Runways → RunwayBorder
    • Taxiways → TaxiwayYellow
    • Taxilanes → TaxiwayGrey
    • Aprons → Apron
    • Parking positions/gates/stands → ParkPos

  2. Converts to GNG format with:

    • Correct folder hierarchy: SCT Entries > FIR > ICAO > Groundlayout > Airport
    • LineString geometry (not Polygons)
    • Color descriptions WITHOUT COLOR_ prefix
    • GNG style definitions

  3. Outputs ready-to-import KML that GNG can directly import

File Structure

mapbuilder/
├── osm_to_gng_direct.py    ← Main script
├── batch_process.py         ← Batch processor
└── output/                  ← Output directory
    ├── CYHZ_gng.kml
    ├── CYYT_gng.kml
    └── ...

Advantages Over Two-Step Process

✅ Simpler: One command instead of two
✅ Faster: No intermediate file I/O
✅ Cleaner: No leftover OSM KML files
✅ Less confusion: Clear input → output

Customization

Add More Airports

Edit batch_process.py:

AIRPORTS = [
    {'icao': 'CYHZ', 'name': 'Halifax', 'fir': 'CZQM'},
    {'icao': 'CYYY', 'name': 'Your Airport', 'fir': 'CZQM'},  # Add here
]

Change Color Mapping

Edit osm_to_gng_direct.py:

FEATURE_COLOR_MAP = {
    'runway': 'RunwayBorder',
    'taxiway': 'TaxiwayYellow',  # Change to 'TaxiwayGrey' etc.
    # ...
}

Troubleshooting

No features found

GNG import fails

  • Verify KML structure in Google Earth first
  • Check folder names match GNG expectations
  • Ensure LineStrings (not Polygons) are used

Network timeouts

  • Overpass API may be busy
  • Wait 30 seconds and retry
  • Script has 60-second timeout

Technical Details

Coordinate Order: Longitude, Latitude, Altitude (KML standard)

Geometry: LineStrings with tessellate=1 and altitudeMode=clampToGround

Description Field: Contains ONLY color name (e.g., TaxiwayGrey), NOT COLOR_TaxiwayGrey. GNG adds the COLOR_ prefix when exporting to EuroScope.

Folder Hierarchy: Must exactly match:

SCT Entries
└── FIR (e.g., CZQM)
    └── ICAO (e.g., CYHZ)
        └── Groundlayout
            └── Airport Name (e.g., Halifax)
                └── Placemarks

Next Steps After Running

  1. Optional: Open <ICAO>_gng.kml in Google Earth to review
  2. Import to GNG: Load the KML file
  3. Export from GNG: Save as EuroScope .txt format
  4. Integrate: Add to your sector file release

Requirements

  • Python 3.6+
  • requests library: pip install requests
  • Internet connection (for OSM queries)

Questions?

This script was designed specifically for CZQM/CZQX vACC workflow based on analysis of actual GNG exports and EuroScope format requirements.

Tested with: CYHZ reference export matching exact GNG structure.