Routes and distances in Port Guide & Distances are calculated using proprietary algorithms:

• Great-circle (shortest path on a sphere) for oceanic passages
• Land and depth avoidance using GEBCO bathymetric data
• Port gates and choke-points adjusted according to maritime practice
• Schematic route line drawn on a simplified map for educational purposes

Limitations:

• Not based on official charts or real-time conditions
• No guarantee of accuracy or completeness
• Not suitable for navigation or safety-critical planning