The goal was initially just to get a polar plot to work. The samples use FunctionSeries hence I was a bit puzzled about the binding - my problems seems to relate to the Angle has to be the Y axis. Using all the Field and AxisKey makes it work.

The bug I have found is with using min and max values on the magnitude axis. I I wen't below min then a line was drawn crossing the center.
This may be a bit of misuse from my side - I should filter the data that are not sensible with my provided min and max values.
However other polar charts that I have worked with draws the approximated line to where the min would be - but it does not cross the center of the polar plot.

The Minimum and Maximum is not respected in the magnitude axis. So plotting below min results in lines drawn to the "opposite" position :-)

When I utilize XAxisKey, YAxiskey on LineSeries and Key on magnitude and angle then it is possible to you the sortedlist when binding to the key and value properties (DataFieldX and DataFieldY)

There was an exception (OxyPlot paint exception Angle Axis Should always be Y axis) - however the examples add the Angle Axis first.

The problem seems to lie in the data binding - what is the appropriate series to use?

There is not much to sample :-)

SortedList<double, double> _d = new SortedList<double, double>();  _d.Add(0, 23); _d.Add(90, 24); _d.Add(187, 25); _d.Add(192, 23); _d.Add(270, 25.5);      var ls = new OxyPlot.Series.LineSeries();//.ScatterSeries();//..LineSeries();  ls.Title = "dummy";  //ls.YAxisKey = plotdav.PlotID.ToString();  ls.ItemsSource = _d;  ls.DataFieldX = "Key";  ls.DataFieldY = "Value";  model.Series.Add(ls);