How To Use A Map

Map Scale
Maps are two dimension representations of three dimensional features. They are drawn to a scale which is printed on the map. Scales such as 1 to 50,000 mean that an object measuring 1 cm on the map will be 50,000 times one cm in real life, or 0.5km.

However since maps are presentations they also use symbols to represent items. These symbols shown later on are not to scale. Thus the symbol for a church is a  + The size of the cross does not represent how big the church is only that it is there.

Contour Lines
A contour line is continuous line of the same elevation (or height) around the edge of a feature. Think of it as the edging trim along each layer of a wedding cake. Each line gives an outline of what a feature looks like at regular intervals of elevation. The closer together the lines are, the steeper the slope. For example the close gathering of contour lines on Mt. Wrongagain represents a steep slope. The spread out contour lines indicate a more gentle slope. UK map contour lines are at 10 meter intervals (Although they used to be at 50 foot intervals), that is each line represents an outline of the mountain 10 meters higher than the line below it. Contour intervals will vary with maps, and it is important to check the interval to interpret the map.

On UK maps contour lines are printed in Brown, with every 5th line thicker. This line will carry a number somewhere along it's length which tells you the height. The intermediate lines you have to work out for your self.

Grid Lines and Grid Reference
On UK Ordinance Survey maps there are two sets of parallel lines which mark the grid lines. These lines are in black and run vertically and horizontally on the map. They represent 1 km squares and enable people to accurately give a position of a place. On the side of the map are a set of numbers (know as Northings) which number each of the horizontal grid lines. On the top and bottom of the map are another set of numbers (known as Eastings), which number each of the vertical grid lines.

To make a grid reference, follow the vertical line to the left of the chosen location down to the foot of the map to read it's Easting - for example 04. Then estimate the number of tenths from the grid line to the location - in this case 5. Therefore the first part of the grid reference is 045. Repeat this with the horizontal grid line just below the location (410). The full six figure grid reference is therefore 045410.

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