Jersey Grid System

Jersey Transverse Mercator (JTM)

This grid uses the Jersey Transverse Mercator coordinate system (EPSG:3109), a local projected coordinate system designed specifically for Jersey. Unlike latitude/longitude, JTM uses metric coordinates measured in meters from a defined origin point.

Coordinate System

• Projection: Transverse Mercator
• EPSG Code: 3109
• Units: Meters
• Origin: The projection has a false origin that places Jersey entirely in positive coordinates
• False Easting: 40000.0
• False Northing: 70000.0
• Central Meridian: -2.135
• Scale Factor: 0.9999999
• Latitude Of Origin: 49.225

Grid Structure

This grid contains 500m x 500m tiles covering Jersey's main island. Each tile is identified by a short ID combining the first three digits of its easting and northing coordinates.

For example, tile 30660 represents a location at approximately 30,000m East, 60,000m North in the JTM coordinate system.

Output Files

• outputs/jersey_grid_main_island.geojson - GeoJSON vector data (WGS84 for compatibility)
• outputs/jersey_grid_map.html - Interactive HTML map with tile labels
• outputs/jersey_grid_map.png - Static visualisation with basemap