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• Maps are divided into a series of squares known as a grid. These grids help us to locate features on the map.
• Maps include a scale to help us work out distance between points on a map.
• Scale is usually written on a map as a ratio. For example 1:25000. Scale can also be shown using a scale bar.

A grid reference is a useful tool for identifying any square on a map. This is done by reading the numbers from the eastings and northings. This gives you the grid reference of the square.

Here are the steps you should follow to produce a four-figure grid reference:

Step 1 - Start at the left hand side of the map and follow the eastings (the vertical lines) along until you come to the bottom left-hand corner of the square you are looking for. Write down the two-figure number, eg 47.
Step 2 - Follow the northings (the horizontal lines) from the bottom of the map up until you find the same corner and make a note of this number, eg 33.
Step 3 - Combine this number with the original number. When put together, these two sets of numbers give the four-figure grid reference. For example, if the easting is 47 and the northing is 33, the grid reference is 47 33.

Always write down the eastings first and then the northings. An easy way to remember this is that you always have to go along the corridor (eastings) before you go up the stairs (northings).

If we want to be more accurate, we can use six-figure grid references. To do this, we need to picture the grid square divided into 100 smaller squares.

Here are the steps you should follow to produce a six-figure grid reference:

Step 1 - Split each grid square into tenths.
Step 2 - Measure or estimate how many tenths of the square the point you are looking for lies between the eastings to the left and right of the point. Write this number after the original eastings. For example, if it was six tenths into the square you would write 476
Step 3 - Repeat this step for the northings and write this down after the original northings. If this was four tenths into the square you would write 334.
Step 4- Put these two sets of numbers together to get the six-figure grid reference: 476 334.

Watch the video at the top of this page to see an example of this.

Maps have different scales depending on what they are used for. The scale tells you how much you would have to enlarge your map by to get the actual size in real life. For example, on a 1:100000 scale map, 1cm on the map equals 1km on the ground.

It's impossible to draw life-size maps so instead a scale is used. Every map has a scale printed on the front. The scale might look like this
1:25000.

This means that every 1cm on the map is equivalent to 25,000cm (or 250m) in real life.

Usually a map will also have a scale bar. This is usually found at the bottom of the map and looks like a small ruler.

Once the scale of the map is known, it is possible to measure the distance between two points. The easiest way to do this is to measure the straight-line distance using a ruler, then convert it using the scale.

However, this method will not work if you are trying to work out the distance on a road that isn't straight.

To measure a road that is not straight, lay a piece of string along the route or use a piece of paper to work out the distance.

Step 1 - mark on the map the route you wish to measure.
Step 2 - place the paper on the map and make a mark at the start of the route.
Step 3- every time the route curves, pivot (turn) the paper to continue to follow the route and make another mark.
Step 4- pivot the paper until you get to the end point.
Step 5- either hold the paper against the scale bar at the bottom of the map or measure it to work out the distance.

For example:

If we measured a road on the map and discovered that it was 10cm, we could then calculate its real length using the scale. If the map scale is 1:25000, we could first work out the length in cm, then convert to metres or kilometres.

Step 1: Convert to centimetres by multiplying the distance you measured by the scale on the map.
10 x 25,000 = 250,000cm

Step 2: Convert to metres by dividing by 100.
250,000/100 = 2,500m

Step 3: Convert to kilometres by dividing by 1,000.
2,500/1,000 = 2.5km

This means that 10cm on the map is the equivalent to 2,500m or 2.5km in real life.