# A Data Processing Framework for Polar Performance Diagrams
## 3 The hrosailing Framework
### Computation of Isochrones
Although the basic hull of these 27-foot yachts is the same for all, every particular model has been turned into a unique personalised version. There exists no ORC classification or similar for these vessels. As far as we know, no polar diagram has been previously obtained for our particular vessel, which is named \"Vela\". For data collection, we used a Raspberry PI with an Openplotter sytem (see [31]), connected to a wireless wind system. Overall, we collected thousands of data points, of which we chose about 185,000 data points for further processing. We only chose data with moderate weather conditions when a specific set of sails were used (full sails). Additionally, we chose 16,000 data points using only the foresail. This data then has been processed via the PolarPipeline using the FluctuationWeigher, CurveExtension and default parameter otherwise. The result is displayed in Figure 13.

Figure 12: All points that can be reached from \((42.5^{\circ},43.5^{\circ})\) in 20 min in different directions. In our experience, the old yacht behaved asymmetrically with wind from starboard and wind from port. The obtained diagram reflects this behaviour very well! ## 6 Conclusions and Possible Future Extensions

The hrosailing framework provides a solid foundation for the scientific work with polar performance diagrams. Other available frameworks and tools (such as OpenCPN) are focused on the needs of sailors and do not provide the same level of control and transparency. Our main goal achieved by the formulation of the hrosailing framework is a research-focused work environment for polar diagrams, which provides a solid basis and many optional choices for experiments and special usecases. The established representation of polar diagrams is via a table. The hrosailing framework provides more kinds of representation suitable for different purposes. Furthermore, the hrosailing framework provides several methods of visualisation. In the implementation, these can be fully customised with the capabilities of the Matplotlib package. Other tools known to us only provide polar plots with very limited visualisation options. While the established tools only use \"black box\" algorithms for polar diagram creation, the hrosailing framework provides a modular data-processing model, specialised in the

Figure 13: Collected data (**left**) and resulting PolarDiagramCurve (**right**) for full sails (first row) or for foresail only (second row). creation of polar diagrams. Using our pipeline model, researchers can experiment with different weighing methods, etc., to fit their specific usecase. While the use of the convex hull to calculate optimal manoeuvres is known in the community, it was, to the best of our knowledge, never precisely formulated as part of a bigger framework. The abstract nature of the WeatherModel allows us to experiment with different approximations of weather forecast data, or even try different artificial weather scenarios. The hrosailing framework also contains flexible algorithms to compute the cost of a trip with different cost functions and isochrone points while considering changing weather conditions along the way. The framework has been implemented as an open-source Python package [30], which utilises the functionalities of established Python packages and is compatible with many established data formats. We aim to further extend the hrosailing framework and the hrosailing package. In the future, some possible extensions are the following:

basic weather-routing algorithms;

handling of weather forecast data in grip format;

use of spherical geometry for coordinates;

machine learning algorithm to choose the right model function for PolarDiagramCurve;

graphical interfaces;

more specific predefined pipeline components and model functions;

methods for online adjustments of a given polar diagram;

support for handling vessel information. Furthermore, we intend to showcase the capabilities of the hrosailing framework in more real-world study cases using different sailing vessels. Conceptualization, R.S.