# Polar performance plugin
Generate performance information based on a polar diagram.

## Data correctness
It's assumed data is already corrected when it's read by this plugin. This can be sometimes be done by the sensor, sometimes upon entry into SignalK using the [calibration plugin](https://www.npmjs.com/package/@signalk/calibration).

## Data sources
The following paths are read
 - navigation.speedThroughWater
 - environment.wind.speedTrue
 - environment.wind.angleTrueWater
 - navigation.speedOverGround (optional)

## Plugin configuration
### Polar diagram
The polar diagram can be configured through CSV notation as used on [ORC sailboat data](https://jieter.github.io/orc-data/site/).

## Example csv
```
twa/tws;6;8;10;12;14;16;20
0;0;0;0;0;0;0;0
46.9;4.23;0;0;0;0;0;0
44.8;0;5.09;0;0;0;0;0
43.5;0;0;5.72;0;0;0;0
42.6;0;0;0;6.22;0;0;0
41.8;0;0;0;0;6.57;0;0
40.8;0;0;0;0;0;6.75;0
41.1;0;0;0;0;0;0;6.93
52;4.57;5.59;6.33;6.87;7.23;7.45;7.65
60;4.93;5.93;6.66;7.15;7.47;7.68;7.94
75;5.17;6.18;6.91;7.37;7.68;7.92;8.31
90;5.29;6.43;7.23;7.71;8.03;8.29;8.57
110;5.38;6.56;7.36;7.84;8.22;8.6;9.31
120;5.2;6.38;7.23;7.76;8.16;8.55;9.36
135;4.65;5.84;6.78;7.43;7.87;8.25;9.03
150;3.92;5.05;5.97;6.7;7.2;7.58;8.17
144.2;4.19;0;0;0;0;0;0
146.4;0;5.25;0;0;0;0;0
146.9;0;0;6.17;0;0;0;0
147.1;0;0;0;6.91;0;0;0
148.3;0;0;0;0;7.33;0;0
171.2;0;0;0;0;0;6.76;0
176.3;0;0;0;0;0;0;7.59
```

The resulting polar after processing can be seen here in the WebApp, looking something like:
![](https://raw.githubusercontent.com/htool/signalk-polar-performance-plugin/main/doc/BandG_polar.png)


### Plugin options
In the plugin configuration you can toggle the following options:
 - Enable calculation/sending of beat/upwind and run/gybe/downwind angle
 - Enable calculation/sending of beat/upwind and run/gybe/downwind VMG
 - Enable sending Target TWA
 - Enable calculation of Optimum Wind Angle (difference between TWA and beat/run angle (depends on beat/run angle)
 - Enable sending of maximum speed angle and boat speed for a given TWS
 - Enable calculation of Optimum Wind Angle (difference between TWA and beat/run angle (depends on beat/run angle)

## Calculated performance data
### Currently supported
 - Upwind / beat angle (performance.beatAngle) 
 - Downwind / run / gybe angle (performance.gybeAngle) 
 - Upwind / beat VMG (performance.beatAngleVelocityMadeGood) 
 - Downwind / run / gybe VMG (performance.gybeAngleVelocityMadeGood) 
 - Target TWA (performance.targetAngle) (equals upwind or downwind angle)
 - Optimal Wind Angle (diff between TWA and environment.wind.directionTrue)
 - Polar Boat Speed (performance.polarSpeed)
 - Polar Speed Ratio (performance.polarSpeedRatio)
 - Plugin option to use SOG as boat speed
 - Wind angle for maximum speed at this wind speed
 - Fill up the ends of the polar diagram
 - Visualisation of the polar diagram
 - Configurable damping alorithm on inputs
 - Extrapolation of polar data towards 0
 - Configurable overall performance adjustment ratio
 - Dots in webapp indicating Polar Speed and Boat Speed
 - Use highest polar speed when going north of Polar

### To-do list
 - Improved interpolation
 - Make moment to do calculation smarter/configurable
 - API to see JSON of polar
 - Create polar from live data
 -- Save polar info to file
 -- Save new record speed for angle in polar
 -- Determine if we're on a steady course to avoid fake records
 -- Configure the resolution of the polar diagram
 - Support multiple polar diagrams
 - Capture heel in polar diagram

## MFD configuration

### B&G
To get the values calculated by this plugin from SignalK to your B&G MFD/Triton2, you need to install the [B&G performance plugin](https://www.npmjs.com/package/signalk-bandg-performance-plugin) and select at least the following values:
 - Polar Speed (Polar Speed - POL SPD)
 - Polar Speed Ratio (Polar Performance - POL PERF))
 - Target TWA (TARG TWA)

To see lay lines you need to set:
 - Settings -> Chart -> Laylines -> Targets... -> True wind angle to 'Actual'

 ![](https://raw.githubusercontent.com/htool/signalk-polar-performance-plugin/main/doc/BandG_Laylines_Target_TWA_to_Active.png)

 - SailSteer screen -> Long press tile to add 'Performance -> Target TWA -> decollapse, choose SignalK'

 ![](https://raw.githubusercontent.com/htool/signalk-polar-performance-plugin/main/doc/BandG_Target_TWA_to_SignalK.png)

Now the Target TWA is coming from SignalK and the laylines will be drawn based on it's value.

![](https://raw.githubusercontent.com/htool/signalk-polar-performance-plugin/main/doc/BandG_Sailsteer_with_laylines.png)

### Raymarine
If you have a Raymarine MFD and can tell more about this, please add to the README or tell me.