For example on wikipedia for Switzerland it says the country has an area of 41,285 km². Does this take into account that a lot of that area is actually angled at a steep inclination, thus the actual surface area is in effect larger than what you would expect when looking onto a map in satellite view?
You just invented the arcology again, lol
It is a near future concept of a fully self sufficient megacity, a sort of intermediate stage towards an ecumenopolis (a planet entirely urbanized with an extreme population density). One popular example would be coruscant, the capital world of the galaxy in star wars.