Geographers use the system of grid references to find their way around maps and to locate places and features on topographic maps. A grid is a system of intersecting parallel lines.
Location can be described by a four-figure reference (area reference) or a six-figure reference (grid reference). The area reference gives a general location, while the grid reference provides an accurate location for a place or feature.
Eastings are the lines which increase in number towards the east; they are vertical lines.
Northings are the lines which increase in number towards the north; they are horizontal lines.
To give an area reference for a place or feature: First, find the nothing grid line before the place or feature.
These two grid lines give the area reference of the grid square.
The area reference is written as AR then four figures, two easting references followed by two northing references.