Rather than memorising hundreds of technical terms, it helps to become familiar with the words that appear most often on maps and in navigation guides. This glossary explains many of the common terms used in cartography, map reading and outdoor navigation.
Use it as a quick reference whenever you come across an unfamiliar word.
A
Altitude
The height of a location above mean sea level. Altitude is commonly measured in metres in the United Kingdom.
Azimuth
A direction measured clockwise from north, expressed in degrees between 0° and 360°. The term is often used in surveying and navigation.
B
Baseplate
The transparent body of a compass, often marked with rulers and map scales to assist with navigation.
Bearing
The direction from one point to another, measured in degrees clockwise from north.
Benchmark
A permanently marked survey point with a precisely known height above sea level.
C
Cardinal Points
The four main compass directions: north, east, south and west.
Cartography
The science and art of designing, producing and studying maps.
Compass Rose
A diagram on a map showing the principal directions, helping users orientate themselves.
Contour Line
A line joining places of equal height above sea level, used to represent the shape of the land.
Coordinate
A set of values used to identify the exact position of a location.
D
Datum
A mathematical reference model used for measuring positions on the Earth’s surface. Different mapping systems may use different datums.
Declination
The angle between true north and magnetic north at a particular location.
Digital Mapping
The creation and use of maps in electronic form rather than on paper.
E
Easting
A measurement used in grid reference systems to indicate how far east a location lies.
Elevation
Another term for the height of land above sea level.
G
Geographic Information System (GIS)
Computer software used to collect, analyse, manage and display geographical information.
Global Positioning System (GPS)
A satellite-based navigation system that calculates a user’s location anywhere in the world.
Grid
A network of intersecting lines printed on a map to help identify locations.
Grid Reference
A series of numbers and letters used to identify a precise location on a map.
L
Latitude
The distance north or south of the Equator, measured in degrees.
Legend
The section of a map explaining the meaning of symbols, colours and line styles. It is also known as the map key.
Longitude
The distance east or west of the Prime Meridian, measured in degrees.
M
Magnetic North
The direction towards which a compass needle points, determined by the Earth’s magnetic field.
Map Scale
The relationship between distances shown on a map and actual distances on the ground.
N
Northing
A measurement used in grid systems to indicate how far north a location lies.
O
Orientate
To align a map so that it matches the direction of the landscape around you.
Ordnance Survey
The national mapping agency for Great Britain, responsible for producing detailed topographic maps.
P
Prime Meridian
The line of longitude at 0° that passes through Greenwich, London, and serves as the starting point for measuring longitude.
R
Relief
The variation in height across the landscape, including hills, valleys and mountains.
Route Planning
The process of selecting a suitable path between two or more locations before beginning a journey.
S
Scale Bar
A graphic line showing how distances on a map relate to real-world distances.
Spot Height
A precisely surveyed point showing the exact elevation of a specific location.
Surveying
The measurement and recording of land, boundaries and physical features.
Symbol
A graphical representation used on maps to identify features such as roads, rivers, churches or viewpoints.
T
Topographic Map
A map showing both natural and man-made features, including terrain, contour lines and elevations.
True North
The direction of the geographic North Pole, used as the basis for many mapping systems.
V
Valley
A low area of land between hills or mountains, often containing a river or stream.
Quick Tips
When reading maps, remember these simple points:
- Bearings are always measured clockwise from north.
- Contour lines never cross each other.
- Latitude runs east to west but measures north and south.
- Longitude runs north to south but measures east and west.
- Grid references are read along the corridor, then up the stairs — eastings first, northings second.
- A larger map scale shows more detail over a smaller area.
Building Your Navigation Vocabulary
Learning a few key mapping terms makes it much easier to understand guidebooks, navigation instructions and topographic maps. As you gain experience using maps and a compass, many of these terms will become second nature.
Keeping a glossary close to hand is an excellent way to reinforce your knowledge and build confidence before tackling more advanced navigation techniques.