Recording & Support -
Help & Advice
Grid References
2. UK National Grid System
Along with the internationally recognised latitude and longitude system, which is based on angles and distances north or south of the Equator and east or west of the Greenwich Meridian, Britain has its ownNational Grid System
. This system is based on metric measurements (kilometres and metres
) from a false origin point off the Scilly Isles.
Figure 1; the National Grid System
To begin with, the whole country is divided into
100km x 100km squares
(figure 1
). These are each labelled with two letters, which form the first part of every National Grid Reference. Kent falls within two of these squares:TQ
(west Kent) andTR
(east Kent).These letters can be found at the top corner of an Ordnance Survey (OS) map.
Figure 2; TQ subdivided into 10km squaresEach of these 100km squares can be further subdivided into 10km x 10km squares (
figure 2
).The names given to any square within this grid (or any further subdivided grid) is a reference to the origin of that square (the bottom left-hand corner),
reading firstly from west to east, and then from south to north
. For example, the highlighted square below (figure 3
) has a grid reference ofTQ75
, and any record within that square would have that reference. Equally, a record with a grid reference of TQ75 could be locatedANYWHERE WITHIN THAT SQUARE
. Consequently, two records with the same grid reference could theoretically be over 14km apart if they were located in diagonally opposite corners.
Figure 3; Highlighted square is TQ75TQ75 (
highlighted square in figure 3
) represents a 10km x 10km square, which can be further subdivided into 100 equal squares of 1km x 1km, as demonstrated below (figure 4
).
If every single 10km x 10km square within the 'TQ' square were subdivided into 1km x 1km squares (
figure 4
), there would be 100 squares both along the bottom and up the side of the grid. Each of these squares would be labelled 0-99, and these are the numbers you find along the bottom and sides of an Ordnance Survey map.
Figure 4; TQ can be subdivided into 1km x 1km squares
Now you know that each square within a standard OS map refers to a 1km x 1km area on the ground. As before the names given to any square within this grid is a reference to the origin of that square (the bottom left-hand corner), reading firstly from west to east, and then from south to north.
Figure 5; Highlighted square is TQ7356For example, the highlighted square in
figure 5
has a grid reference of TQ7356, and any record anywhere within that square would have that reference.
