What is a map?

This may sound a stupid question, but it is always good knowing the answer before even attempting any form of navigation. You wouldn’t trust a driver if they didn’t know what a car was!

The dictionary explanation is ‘a diagrammatic representation of an area of land or sea showing physical features’. This means anything from a globe to a sketch of how to get to your house is a form of map. Maps show different detail for different uses. A road map may show every road but they will not show trees or land height.

The largest scale map in common use is a map of the stars of the night sky. Then the next size is the globe. Then they go down in scale to Continent, Country, County or area. This is followed by navigational maps. These maps are commonly produced by Ordnance Survey. These cover an area of roughly 20 to 40 km across. This normally covers a number of towns and gives a lot of detail.

The Changing Landscape

The landscape is constantly changing. New houses get built, fences move in farmers fields, new footpaths are opened and old ones are closed. This means a map of 50 years ago would look a lot different to one of today. You cannot instantly change a detail on paper map, so your maps need to be replaced as they get old to show you the changes.

Scale

The size or scale of map is measured as a ratio. The common navigational map used in Scouting is the 1:25 000 scale (said as 1 to 25 000). This is 1 measure on the map to 25 thousand on the ground. So 1cm on the map would equal 25 thousand centimetres on the ground, or 250 metres.

Once you know this, it is fairly easy to measure distances on a map. Most compasses will have a distance measurement on them suitable to your map. If not, then you can measure in centimetres with a ruler and divide by 4 to give kilometres on the ground.

For example:

6 cm on a map

divide by 4

= 1.5 kilometres on the ground