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1. Do all maps show real places?

Maps can show a scaled-down version of a real place, or entirely fantastical realms, such as Tolkien's Middle Earth. They can also be a mix of real and imagined space, as in local development plans or planning applications.

These plans show how a place could look in a possible future. Sometimes the finished work is very different to the early proposals and therefore plans can show things which never existed.

Equally, changes can be made which are never captured on a map. The feature may simply not be selected for inclusion on the map, be deliberately censored, such as military installations, or go unrecorded in the case of a temporary building or a shifting sandbank.

2. How are features selected?

Maps are created for specific purposes, which means the information they contain needs to be carefully selected.

Understanding both why the map was created and how it will be used, the cartographer has made the selection on your behalf, editing out other information. For example, a map of the rail network only includes routes and stations, to help you plan your train journey.

If selected, features are generalised by reducing complexity of detail, or are represented by symbols. The railways on the map do not show every curve of the track. This makes it clearer for you to read the map, uncluttered by surplus information.

Generalisation also enables more information to be shown in a smaller space. One topographic map, such as an Ordnance Survey sheet, can show 100 million discrete pieces of geographic information!

3. Why do maps have scale?

Scale enables you to relate the map to its equivalent space in the real world.

You'll find the scale written on the map as a written statement, like 'one inch to a mile', as a representative fraction, 1:63,360, or illustrated in a scale bar. The fraction shows the number of times the area has been reduced, or shrunk, from its real size. Scale enables you to measure distance.

The scale of a map determines both the complexity of detail depicted and the amount of ground covered. Small scale maps cover large areas, such as an entire country or continent, and must be generalised. Large scale maps or plans, of buildings, parts of towns or individual farms, show a small area in detail.

4. Why do place names change over time?

Just as gossip changes in the telling, so place names alter in the oral tradition. If you imagine each person writing down the name, spelling it as they like, then you have some idea why place names appear differently on maps through time.

Add deliberate political intentions of obscuring a language or exerting control over an area, coupled with accidental losses in translation and it is easy to see why an individual place may be represented by several names on a map, for example Striveling, Sterling, Stirling, or, Byzantium, Constantinople, Istanbul.

A definitive gazetteer for Scotland of 95,000 place names has only just been agreed.

5. How are hills shown on a flat map?

It is difficult to show a bumpy landscape on a flat piece of paper or a screen. The cartographer has to choose the best of the techniques available at the time to match the purpose of the map.

From the earliest pictorial portrayal of hills, through hachures, hill-shading, contours and gradient tints, each method of depicting relief requires you to use your imagination. You, the map reader, need to use these images, symbols and lines to visualise the valleys and hills and see the shape of the land.

A hill walker would soon get lost using a pictorial map!

6. Why use symbols?

Symbols, including icons, colours and styles of lettering, declutter a map. This makes it both clearer to read and capable of carrying more information within the limited space. The symbols and styles add emphasis to selected features.

Symbols can also be used to depict social constructs, such as civic and national boundaries.

The use of a set of symbols throughout a whole series of maps, means that if you are familiar with the sheet for your local area you can easily identify the same types of features in a place you have never visited. By applying the same cartographic rules and set of symbols across the series no one place is chosen for special treatment, inferring equality across the region. This is particularly true of national mapping, such as the Ordnance Survey.

7. Do maps go out of date?

Using an old road map when travelling may lead you astray, but as a record of the road network at the date of its creation the map still has a function. You can use it to study how the road layouts have changed. Similarly, civic and national boundaries move over time, reflecting the changing political environment.

All maps reflect the time at which they were made, enabling you to travel not only figuratively through space but also through time.

The date of the content of the map will be earlier than the publication date, due to the length of time between surveying and printing. Printing plates were re-used by mapmakers, sometimes for decades.

8. How do maps show human activity?

Many maps show topography, but they also record human impact on the landscape. Settlements, bridges, roads and railways all appeared on maps as their importance and influence grew.

Maps can also show socially constructed landscapes, with political boundaries at all levels from civic districts to international borders. Although often based on rivers, ridges or watersheds, these boundaries may have little or no physical presence, but much influence on people's lives. The maps themselves become evidence of the boundaries' existence at a given point in time, either demonstrating an agreement, or becoming a focus for contention.

Maps can also be used to plot the distribution of populations and their many properties and activities.

9. How is the spherical world made flat?

Flattening our round world onto a piece of paper or screen is a particular problem for cartographers. The answer lies with mathematical projections which enable the surface of the globe to be sectioned and stretched, like removing the peel from an orange.

Each projection inevitably distorts some part of the world on the map: the larger the area shown the greater is the distortion.

There is no perfect projection, only the one which best fits the map's purpose, whether used for navigation, or to draw attention to a particular part of the world. Scale varies across the world map, so is usually only given for the Equator.

10. Why is north to the top?

Many early maps pointed east or to the Orient. The cartographer would include a wind or compass rose to show direction. Maps can be “orientated” in any direction.

Following the development of latitude and longitude, using astronomy to fix location, maps could be successfully used for long distance navigation, and pointed towards the prominent north star (in the northern hemisphere). Gradually this became accepted, with a grid or graticule to show the degrees and minutes of latitude and longitude removing the need to include the compass rose.

On modern maps an arrow symbol may be used to show the difference between true and magnetic north.