XData and YData for plotm (mapping toolbox, drawnow)

I have a lat/lon track which is updating in time via an interpolation to gather FPS.

The code is already slow due to drawnow, as on a normal plot I would call set() to update the properties, this doesn't seem to exist with plotm.

Also, the lat/lon tracks are in segments, meaning there is a for loop for each segment. Using drawnow, by the final segment the speed of the plot update is unbelievably slow, can someone explain why drawnow seems to stack rather than refresh.

Any suggestions to speed up the animation?