Signal K Utilities

This project contains some utilities to be used in the development of signalK plugins. The utilities mainly deal with getting data from the signalK server, processing this data and sending it back to the server for further use.

the MessageHandler class

This is the core class for getting from the signalK server and sending it back. The MessageHandler can deal with exactly one path. It can be used to get a delta value from the server once it comes available and to send a modified or newly generated value back to the server.

the SmoothedMassageHandler class

This class is a decorator to the MessageHandler class. It is used to smoothen an incoming delta using 1 of three available smoothers: ExponentialSmoother, MovingAverageSmoother, KalmanSmoother. The class does support writing smoothed deltas back to SignalK.

the Polar class

The class combines two MessageHandler classes using two paths that together contain a vector value (in polar format). For example Speed over Ground and Course over Ground. In addition to getting data from and sending data to the server the class has also methods to perform calculations with vectors, like adding two vectors, scaling or rotating a vector.

the SmoothedPolar class

This class is a decorator to the Polar class. It is used to smoothen the incoming vector using 1 of three available smoothers: ExponentialSmoother, MovingAverageSmoother, KalmanSmoother. The smoothedPolar class does not support calculations. The class does support writing smoothed vectors back to SignalK.

the PolarTable class

This class is used for managing and interpolating sailing boat polar performance data. It loads polar tables from CSV data in Jieter format containing boat performance across different True Wind Speeds (TWS) and True Wind Angles (TWA). The class provides interpolation capabilities to get smooth performance data for any wind condition, including optimal sailing angles, speeds, and VMG calculations. It supports performance adjustment scaling and handles both port and starboard tack data through automatic symmetry.