A while back I took a train journey from a town north of London to Bristol.  I had my netbook along with me and had planned to get a bit of recreational coding done.

In the end I started playing around with the examples on one of the Processing libraries I'd not used very much before - the excellent GSVideo.  The example was a slit scan program and I used it to make a composite picture of the entire journey from London Paddington to Bristol Temple Meads.

The program was set up to take the centre line of pixels from the netbook webcam and write it to the screen.  On the next frame the centre pixels were sampled again and written on the screen to the right of the last line.  This process continues until the window is full and then starts to over-write the image.

I made a small modification to the program - when the window was full it would now be written into a file before anything was over-written.  For each save the index number in the file name was increased so I was able to build up a bank of images.

I set up the webcam to see out of the window (I got some odd looks since this required me to turn the laptop sideways) and checked to see if it seemed to be working, it was an so all I had to do was keep it going.

I composited the images together (I was lucky that I got a non-prime number of captures and was able to fit them into a rectangle) and the final image is interesting - the journey starts at the top left and ends at the bottom right. It's similar to the weird-looking finish line photos that you see on athletics competitions sometimes; when the train stops at a station you can sometimes see people walk past the camera.

(The rather odd changes in brightness are simply the automatic adjustments of the webcam trying to deal with the changing light that it could see out of the window)

The image above is a part of the journey where the train stopped at Reading. You can see the logo of the newsagent 'WHSmith' stretched over the whole of the stop. There's a full-resolution version linked to the image above; be careful it's 6600 pixels wide & 650kb...