Why North is Up Map Conventions and Where They Came From

Pick a map. Any map really. Chances are that the map is oriented with North at the top. But why is that? Maps are a visual language onto themselves, rich in iconography and symbols, and especially rich in mutually agreed conventions. So rich, in fact, that you will take many for granted without even realising it. In Why North is Up, cartographer Mick Ashworth leads the way through the history of cartographical conventions, introducing when and why they came into being, and how they have changed over time. And as a book published by the Bodleian Library, it is very attractively illustrated with a large number of maps from their – and other – collections.

Ashworth is particularly suited to write this book, being director of the mapping company Ashworth Maps, a consultant editor for The Times Comprehensive Atlas of the World, and a fellow of the Royal Geographical Society. He wears his knowledge lightly though, covering a range of topics in 30 chapters and seven parts in a very accessible and concise style.

To read a map, you need to understand the basics, so Ashworth first introduces latitude and longitude, map projections, grids, and scale. Many map conventions discussed in this book turn out to have very deep histories. One particularly striking example is the use of map grids, as shown on the stone-carved map of China, the Yu ji tu, dating back to 1137 (Brotton discusses this map more in-depth in A History of the World in Twelve Maps). Knowing where you are on a map requires coordinates. Latitude, your north-south position, was fairly easy to determine. But longitude, your east-west position, was a far more challenging problem to crack for map makers (see also The Illustrated Longitude).

Similarly, illustrating a three-dimensional spherical object two dimensions is a great challenge. You try flattening an orange peel on a table. There have been many approaches before Gerard Mercator’s technique became the preferred solution (see Flattening the Earth and Mercator: The Man Who Mapped the Planet). Like every map projection, it has a few well-recognised drawbacks that Ashworth shortly discusses here.

With the basics covered, the book proceeds to discuss, amongst others, map symbols, how to show relief, the typography and placement of names, and the drawing of boundaries. The final section covers thematic maps, specialist maps, and modern maps online. Throughout these sections, the book bristles with interesting tidbits.

To draw anything on a two-dimensional sheet of paper you have three options: points, lines, and shapes. Add colour and shading, and you have many ways to show features on a map. Certain traditions, such as representing roads with double lines, can be found on Roman maps and are still used today. Others, such as the use of small vignettes to show towns and cities, have fallen by the wayside. Mapmaking used to be full of artistic expression, featuring embellishments both on maps and around their borders, with seas frequently boiling over with monstrous creatures (see also Sea Monsters on Medieval and Renaissance Maps and Sea Monsters). It is hard not to feel we have lost something with today’s functional maps, and perhaps it explains the continued popularity of old maps.

For me, one of the most fascinating and beautiful sections is that on showing relief. To safely navigate a ship required accurate information on water depths that had to be shown on maps. As Ashworth remarks, the shape of the seabed is not so interesting to map users – they just want to ensure a safe passage. On land, it is a different matter though, and a range of techniques has been used to represent hills and mountains, including hachures (patterns of fine lines), contours, and colours. This section has allowed Ashworth to select some outstanding historical maps, which are as beautiful as they are functional.

As with many other aspects of science, warfare and military interests drove the development of technology, requiring both more accurate maps, but also providing new kinds of information to show on maps. Next to plain and simple topographical maps that show the lie of the land, Ashworth briefly discusses military maps, hydrographic charts, geological maps, and the more infographic-like thematic maps that can plot all sorts of information.

The archetypal geology map that had a huge influence on how we understand our planet and the concept of deep time was William Smith’s Delineation of the Strata of England and Wales (see also The Map that Changed the World). A famous example of a thematic map is Charles-Joseph Minard’s map showing the size of Napoleon’s troops entering and returning from Russia during his 1812 campaign, hammering home the astounding loss of men (see also The Minard System).

The revolution of online mapping, which has put a near-infinite amount of constantly updated maps in the palms of our hands, is an appropriate topic to see out the book. As with other chapters, the information presented is brief. German geographer Albrecht Penck’s vision and failed attempt to produce an International Map of the World strung itself out over almost a century. One cannot help but feel that his story is a book waiting to be written, and Ashworth provides a tantalising précis here. If Penck was alive today, he would be astounded by what Google has managed to achieve.

So, why is north up? As Ashworth convincingly shows, every map convention has a story to tell. This particular one was a combination of historical precedent (Ptolemy’s map-making instructions), new technology (the magnetic compass, which happened to point in that direction), and the choices made by Mercator when he made his influential world map, solidifying this convention.

Maps fascinate many people, and though most of us understand them to some degree, few will have the time or dedication to ever read a textbook such as Elements of Cartography. Fortunately, Ashworth provides an eminently readable introduction that is beautifully illustrated with a wide selection of carefully reproduced maps. Both a beautiful book to own and to give, this is a must-have for anyone with an interest in maps.