# How to read map co-ordinates

This page will show you how to read map co-ordinates on the *Ordnance Survey* map excerpts published throughout this New Forest National Park web site.

OS maps use a grid system that divides the country into squares of **100km x 100km**, with each square having a two letter reference. The reference for the New Forest area is **SU** and these letters prefix the numeric grid reference. Each square is then divided into 100 smaller squares, each one representing **10 sq.km**.

These 10km dividing lines are numbered from 1 to 9, starting from the **bottom left corner** of the 100km square, and so increase left to right (*'eastings'*) and upwards (*'northings'*).

On small scale maps, such as the extracts throughout this web site, these 10km squares are divided again into **1km x 1km** squares, with the eastings and northings numbered 01 to 99 through each separate 100km square. In the image below, easting 31 and northing 10 are circled to illustrate this:

## How to read 6 digit grid references

Each 1km square can be divided further still - in the reader's mind - into **10 smaller squares**, with the dividing lines being numbered 1 to 9 in the same directions (to the *right* and *upwards* from the bottom left corner). This smaller 'mental' grid, the red lines in the image below, will pinpoint an exact location within the 1km square.

So to find a place using a given grid reference, simply locate the appropriate easting first (*the first two digits of the reference*) and then the appropriate northing (*the 4th and 5th digits*). This intersection will be the **bottom left corner** of the square that you need to divide up in your mind. Then gauge the distance across and up this square in 1/10ths, according to the 3rd and 6th digits of the reference.

**Example from the above excerpt:** the grid reference for Ashurst railway station is SU**334102**.

Greater accuracy can of course be achieved by using an **8 digit** grid reference. Here, the distances following the 3rd and 6th digits of a 6 digit reference (*the red lines above*) are divided again into 1/10ths.

Using the same example, the 8 digit grid reference for Ashurst railway station is SU**33381012**.

**© Copyright information** - Both map extracts shown on this page, along with all extracts throughout the New Forest National Park website, are Crown Copyright and have been published under License no.**WL8732**. The extracts cannot be reproduced without consent.

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