Maps: Overview


A picture of some paper mapsWhat is a map?

The Oxford English Dictionary defines a map as "A drawing or other representation of the earth's surface or a part of it made on a flat surface, showing the distribution of physical or geographical features (and often also including socio-economic, political, agricultural, meteorological, etc., information), with each point in the representation corresponding to an actual geographical position according to a fixed scale or projection" (OED, no date).

Maps have been around for hundreds of years, and are used for a range of purposes, from simple navigation to defining boundaries at international or local levels.  

The art of making maps is know as Cartography.  The science/method or making a survey of land features is known as Surveying.

History of maps

In the UK maps have a long history, and our main mapping authority - The Ordnance Survey - was created in 1791 (Ordnance Survey, 2023).    Detailed maps were needed by the military in order to plan campaigns and move troops, and the Board or Ordnance (the Ministry of Defence of its day) had commissioned surveys to be done of Scotland, and of England's southern coasts.

William Roy was only 21 when he was tasked with surveying Scotland, a task which took him eight years to complete.  He had a life long mission to create a map of the whole of Britain unparalleled in its accuracy, and when he died in 1790 his vision of a national survey of Britain was almost completed.

The first map "published" by the Ordnance Survey for public consumption in 1801 covered Kent - an area vulnerable to French invasion.  The emphasis was on hill shading and communication lines, showing it's military origins.  As time went by other features would be added to maps to allow them to be used by a wider audience.

Features of maps

There are some common features of maps.  Not every map will have all of these, but if they do, the principles are the same regardless of who made the map.


All modern maps are drawn to some sort of scale. Scales are represented by a ratio of numbers, such as 1:25,000.  The first number represents the distance on your map, and the second number is the distance of actual land.  So, a scale of 1:25,000 would mean one centimetre on the map represents 25,000 centimetres of actual land.  In addition to the scale, you may also find scales written in terms of distances rather than a ratio - for example 4cm to 1km (four centimetres on the map = one kilometre of actual land).

Keys / Legends

Maps use a key or legend of symbols to display common land features.  These recognisable icons are usually displayed at the bottom of a map (or near the beginning of a book of maps).  Common features identified on maps include, churches, post offices, schools, hospitals, train stations, airports, car parks etc.  

Where maps cover an area of land that has various boundaries - such a county boundaries - you may also find a key/legend showing different lines (usually a variety of dashed lines) to identify these different boundaries.

You may also find routes, such as public rights of way, footpaths, and bridleways etc. marked on a map.  Like boundaries these are identified with by special "lines" of small dots, dashes, or other symbols.


Many maps split the land into "grids" - a series of squares which are numbered allowing you to identify features of the land via "grid references".  The vertical lines are called Eastings, and the horizontal lines are called Northings.  Grid references are written as letters and numbers - and always come in the form of Eastings, then Northings (Along the corridor and then up the stairs!).

For the UK the grids are maintained by the Ordnance Survey.  They have split the UK into 100km squares - each square is identified by two letters.  In turn - these squares are further subdivided into 10 squares, and each of these 10 square is divided into another 10 squares.  You can find out more about grid references and how they work by visiting the Ordnance Survey website (see the "Useful Resources" box on the left for the link).

Why do we use maps?

Maps are used for a variety of reasons - and depending on the reason, the type of map and the information it gives will differ.  In terms of civil engineering maps are very important when planning large building projects.  They can help plan routes for new train lines, point out man made "furniture" (such as buildings, roads and electricity pylons, etc.), show us nearby water supplies, and even show us what's underground - all things useful when looking for a site to build a new civil engineering project on.

Types of maps

There are many different kinds of maps and the below list is just a few of the more common ones.  

  • Street maps - show street layouts with road names - such maps usually also include an index of road names so you can easily locate a particular road
  • Road maps - usually larger in scale showing the major roads of an area such as Motorways and major A/B roads.
  • Topographic maps - show the height of the land using contour lines - useful for planning tunnels or navigating around hills etc.
  • Atlas - usually a book of maps showing the location and boundaries of countries around the globe.
  • Nautical maps - used to navigate at sea, and include water depths and flow rates
  • Underground maps - maps showing where all the utility and tunnels are underground

There are other types of maps - used to show boundaries, or display statistical data in a geographically way.  For example:

  • Heat maps - showing the "hot spots" of things such as density of populated areas.  
  • Political maps - showing the boundaries of voting wards in a particular area, or even the results of each area from an election. 
  • Time zone maps - showing the times zone various (parts of) countries are in

So - your choice of map to use will depend heavily on the information you need.

Historical maps can also be useful to determine what was on a piece of land previously - something which could effect where you build.

Digital mapping

Maps have a long and established history of paper rolls or large folded pieces of paper.  Books of maps have also been published - but with the internet and modern mapping techniques, maps have become far more accessible and interactive.  We now use Global Positioning Systems (GPS) to help us find our way around the globe.  A series of GPS satellites orbit the earth, and communicate with navigational aids, telling you exactly where you are in the world and displaying that location on a digital map.

Digital mapping has also increased the use of three-dimensional maps allow users to look around locations or visualisations of an area in a computer model.  Large scale building projects use such 3-D representations to demonstrate virtually what the finished build would look like.

Maps and locations

An image of a house number displayed on the outside wall of a houseGrid references are all well and good, they can identify a location to a 1m by 1m square - but they aren't exactly user friendly, so in populated areas we tend to use postal addresses in the UK, specifying specific buildings in a specific road or street in a town or county.  In the UK, the postcode system was introduced in the mid 1800s (Postal Museum, 2023).  Postcodes identify the Post Town, and then a group of addresses in that Post Town.  Each postcode corresponds to around 15 addresses, however large business or corporations may have their own unique postcode for example the House of Commons has a postcode of SW1A 0AA (Wikipedia, 2023).

Postal addresses are all well and good to identify a residence in populated area, but they do rely on road names, as well as houses/buildings being named or numbered.  This is an issue in countries where road infrastructure is poor and road names do not exist.  This becomes especially important for emergency services - only knowing a vague area doesn't help locate an injured person in an emergency - especially if they are no-where near a road in the first place, like halfway up a mountain or in the middle of a desert.

To tackle this problem, What Three Words decided to divide the entire globe up into 3m x 3m squares, and give each square three words to identify it.  With a simple app you can tell people where you are quickly and within a 3m square anywhere in the world, making you easy to find, and allowing emergency services to get to you quickly.  Give it a try - visit the What Three Words website and enter ///part.worker.needed and see what you find!

Maps as visual aids

Some maps are not always accurate, and deliberately so. The London Underground map is a prime example.  Its focus is on the connections between different tube lines - rather than an accurate depiction of where the stations are in relation to each other.  In 2014 a map was released under a Freedom of Information (FoI) request to Transport for London (TfL) which shows a more accurate underground map with the emphasis on where the stations are on a map of London and where tunnels are a bit more "wobbly" than the traditional London Underground map shows (Transport for London, 2019).

A heat map showing where the most reported cases of Covid-19 were in the United Kingdom at the time the map was madeHeat maps are another example - they are data visualisation tools used as a way of showing statistical data, but in an easily digestible visual form.  For example the map on the right shows the number of reported COVID-19 cases in the UK at a specific point in time.  The red areas show the highest number of cases.  Emergency services can use such maps to decide where to best deploy their limited resources.  Heat maps use a colour code or key, and usually the darker the colour the higher the number of the statistic being shown.

Into the future

Mapping has come a long way from the crude sketches in the middle ages through to the modern use of GPS.  These days you can even get maps of underground structures - showing you where all the utility lines are. Many utility lines are under the road network, and it's easy to strike a pipe or cable unless you know exactly where they are.  The UK government has commissioned the National Underground Asset Register (NUAR) which will provide information on utility lines and hopefully prevent accidental pipe/cable strikes, saving an estimated £350 million a year (GOV.UK, 2023).

Satellite imagery is also used to monitor areas over time - useful if you are looking at the effects of environmental disasters, or global warming.

The world of civil engineering uses maps a lot, from scouting locations for new builds, and planning routes for new roads and railways through to town planning.  Maps are constantly updated as the landscape changes and new structures are built, so ensuring you have up-to-date maps is vital.

Who knows - perhaps something you build will end up on a map?  


GOV.UK (2023) 'First UK areas access new digital map of underground pipes and cables', 5 April [Press release]. Available at: (Accessed: 12 May 2023).

OED (no date) map, n.1 Available at: (Accessed: 28 February 2023).

Ordnance Survey (2003) Ordnance Survey History Available at: (Accessed: 9 May 2023).

Postal Museum (2023) Postcodes. Available at: (Accessed: 12 May 2023).

Transport for London (2019) FOI request detail: Geographically accurate Tube map. Available at: (Accessed 12 May 2023).

Wikipedia (2023) Postcodes in the United Kingdom. Available at: (Accessed 15 May 2023)

Picture credits

Maps by Andrew Neel is used under Unsplash licence

135 by Robert Boyer is used under Unsplash licence

Covid 19 heatmap by Who called me is used under CC-BY 4.0 licence

Useful resources

Using maps in assignments

Maps are covered under copyright law, so you will need to check if you can use a copy of a map in your assignment.  Please contact our Open Research & rights team on to get advice.  See also their information regarding maps on their web pages under Still images (expand the map section at the bottom of the page).

Referencing maps in assignments

Need help? Come and ask!

If you need some quick advice on finding information or referencing, then come and ask me.  Below are the times I will be on the LibSmart Desk on the 1st floor of the library.