If you depict the metro lines and on a geographic map of the city, you will see a closed loop that does not represent a perfect circle. But, on the associative level, this loop is easier to remember in the form of a circle.
Usage of circular line pattern is the main principle of the map’s design. They simplify the perception of the map by putting the visual accents and dividing the map into round segments.
In addition, these lines, forming a circle, are unique as they intersect with all the main lines of the system.
By the year 2030, another circular line will run around Paris.
In 1992, Paris public transport operator RATP introduced a new logo featuring a silhouette of a girl looking up, which symbolizes the Seine river passing through Paris, represented in the shape of a circle.
Nowadays, it can be seen on all metro trains, buses, tickets, and Paris city maps.
Labyrinths are intentionally created with a lot of turns, to complicate the process of finding your way.
As the goal of the new map was to help people to find their route quickly, it was necessary to straighten the lines as much as possible and depict interchange nodes in a more clear way.
On the new map, there are two times less line bends then it is on the classic Paris transport map. In order to achieve this result, a 30° grid has been selected which allowed to increase the number of converging lines without interfering with the rhythm of the graphic image.
Typically, transport maps employ a 45° grid.