public void RenderArrow(ILayer FP_point, LayerList layerList, double lat, double lon, DateTime time, double heading)
{
int symbolHandle = FP_point.CreateSymbol("arrow", 0); //Create symbol 0 = doesn't already exist
//add line to symbol from pixel 0,0 to 0,1 (use this to change where degree 0 is)
FP_point.AddLineToSymbol(symbolHandle, 0, 0, 0, 2);
FP_point.AddLineToSymbol(symbolHandle, 0, 2, 1, 1);
FP_point.AddLineToSymbol(symbolHandle, 0, 2, -1, 1);
//add created symbol to layer with lat long and rotation
FP_point.AddSymbol(layerList.Layer, symbolHandle, lat, lon, 20, heading);
}