Area N6E3 (or simply [3,6]) refers to the area on Earth (or possibly other planet) defined by ϕ = ( 50 ∘ , 60 ∘ ) , λ = ( 20 ∘ , 30 ∘ ) {\displaystyle \phi \,\!=(50^{\circ },60^{\circ }),\lambda \,\!=(20^{\circ },30^{\circ })} interval of latitude and longitude respectively.
This article is about N6E3 area on Earth.
http://encyclo.wikia.com/wiki/World%27s_Neutral_Map