Drawn from our collection of more than two million maps and atlases, together, the maps in the 'You are Here' exhibition explored the answers to familiar questions, including:
from 'A new map of the world',
- Why is north at the top?
- How do you flatten a spherical world onto paper?
- How do you show hills on a flat map?
- Why do maps have a scale?
- Do maps go out of date?
Why is north at the top?
North is not always at the top: maps can point in any direction. Many early maps pointed east or to the Orient. The cartographer would include a wind or compass rose to show direction.
Following the development of latitude and longitude, and using astronomy to fix location, maps could be used for long distance navigation. They then typically pointed towards the north star.
'A new map of the world',
How do you flatten a spherical world onto paper?
Flattening our round world onto a piece of paper or screen is a particular problem for cartographers. Mathematical projections section and stretch the surface of the globe, like removing the peel from an orange.
There is no perfect projection, only the one which best fits the map's purpose. Each projection inevitably distorts part of the world on the map.
How do you show hills on a flat map?
The cartographer has to choose the best of the techniques available at the time to match the purpose of the map.
Many methods of depicting relief have been used, including:
- Hachures: A short line on a map that indicates the direction of slope
- Hill-shading: Shadows drawn on the map to create a three-dimensional effect
- Contours: A line on a map that connects points of equal height
- Gradient tints: Relief depicted by a gradation of colours, between contour lines.
Why do maps have a scale?
Scale enables you to relate the map to its equivalent space in the real world.
The scale is written on the map as a written statement, like 'one inch to a mile', as a fraction, ratio, or illustrated in a scale bar. The fraction shows the number of times the area has been reduced, or shrunk, from its real size.
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. Large scale maps or plans show a small area in detail.
Do maps go out of date?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.
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.
More map questions were in 'You are Here', our exhibition on maps, which ran at the National Library from 22 July 2016 to 17 April 2017.