Also, note that the OpenCycleMap tiles you are using request specific attribution: http://www.thunderforest.com/terms/
Here is the script to generate the GeoJSON file: https://github.com/davidbailey/py/blob/master/walkbike2015.p...
Thanks for the info about attribution. I've updated the page.
Also, note that the OpenCycleMap tiles you are using request specific attribution: http://www.thunderforest.com/terms/