Having thought about this since I posted that, I suspect there is a confusion as to what we mean by our 'primary' means of navigation. For my money saying that GPS is my primary means of navigation means that once I am in the air I use the GPS as the means of determining whether I am on track, rather than using VOR, ADF or dead reckoning. None of this for my money means you should not draw lines on a chart and follow your progress along those lines when you are in the air. I certainly do not mean that I use the GPS map to avoid the need to use a chart! In my case I have an autopilot coupled to the GPS and can have the track error from the GPS displayed on my normal CDI instrument. So the map on the GPS normally displays where I came from, where I am going to and a pink line in between with hopefully a little aeroplane on it sitting on the line pointing somewher in the direction of the line. It also displays the odd airfield en-route if they are large enough for my settings to allow them to show up. Occasionaly you see a wobbly line on it which is a coastline. Sometimes I have the airspace displayed so I can see when I am reaching the FIR over the channel. I can change the detail displayed by repeated pressing of the CLR key. Works for me, and as far as I am aware, minus the autopilot coupling, can all be done with the Pilot III.