Paris metropolitan area is getting nowdays a much wider definition, with the aim of adjusting it to the modern era of rapid passenger trains, which cruise at a speed of 200 km per hour and more and extend the daily commuting distance to 200-300 km from the city center.
The question is how to define the new pattern of expanstion of paris: will it be circular, rectangular or perhaps ameba shape. By drawing few abstract lines the entire planning will be determined.
After looking at a large scale map which show the main routes and cities of France and its neighbors it is clear that the expansion pattern of Paris megalopolis should be that of a simple star. Symetrical '5 corners star' is the expanding pattern of the city for hundreds of years.
The 5 corners of this star are:
North - London
North East - Frankfurt
Soutn East - Geneve
South West - Bordeau