LOL. Thanks
There now follows a sufficiently roundabout answer to Dell's question to illustrate why I might not be doing this for every ride
How its done:
1: Ride to Southend and back with a GPS and timelapse cam taped to the boom, taking ISO400 shots at an interval of 45 secs.
2: Locate the 1000(+) images that are part of the ride.
3: Rotate each (camera is side mounted), then resample to 1280x780, padding to full frame left with black
4: Import to your video editor of choice, setting the duration of each still to ~2 frames. Check it.
5: Concatenate the GPS tracks using your GPX editor of choice and upload to ridewithgps.com (here's mine:
http://ridewithgps.com/trips/111963) - This is the only free player I know that shows a real time ride, stopping and starting inline with the time signature on the GPS track.
6: Set the view mode of ridewithgps.com to 'terrain', speed to 32x, and play back the entire ride full screen.
7: Seven times a second, print screen to a file (use a screen grabber) to build a second array of stills showing the scrolling map.
8: Break the resulting files into folders for each journey leg (start > Woodgrange, Wood > Services, etc..)
9: Import each folder to a second track in your video editor of choice, setting the duration of each still to ~1 frame.
10: Shunt the second track so that the centre frame is approx 1/4 from the left hand edge.
11: Crop the right hand side of the second track so that it lays adjacent to the cam footage from track 1.
12: Use timestretch/resample on each leg until the start/ends match up
13: Apply an 'invert' action to the luminance channel of each 'night' frame in the second track. NB: You MUST use the luminance channel. If you apply on the (default) RGB channel, you will see purple parks and orange rivers. Luminance will flip the low white features to black, whilst retaining the colour information of the mids.
14: Find some music, resample to fit.
15: Export to an encoder, make sure nothing is blocking the fan, and walk away.
16: Play the exported file and realise the map is zoomed out too far to read at speed. Repeat steps 10,11 and 15 with a zoom factor applied to the second video track. Loop as necessary.