Electronic Navigational Charts for Visualization, Simulation, and Autonomous Ship Control

Autonomous control and high-level decision-making for autonomous ships in complex environments are largely dependent on real-time navigational data from sensory systems and nautical charts. Visualization and manipulation of data contained within electronic navigational charts (ENC) or hydro/geographic information systems (HIS/GIS) is generally handled on the application or operations level. However, accessible and open-source application programming interfaces (API) for displaying and managing spatial bathymetry or other related sea-faring data for research and development are scarce. This work presents an open-source ENC visualization and manipulation API implemented in Python, with heavy emphasis on accessibility and simplicity. The current version of the package provides tools for displaying marine polygon data such as ships, ocean depths, reefs, and shallows, using the transverse Mercator projection. Additionally, polygon- and point-based transformation and calculation methods for application development based on spatial geometry, path planning and numerical optimal control are implemented. Usage of the spatial methods are demonstrated by examples involving high-level path or trajectory planning, optimization, and assisted decision-making for autonomous and remote-controlled ships.