A Cartload of Cartography 3: Projections and the Present Day

[Tar-Palantir]

A Cartload of Cartography 3: Projections and the Present Day
By Tar-Palantir

This is the third and last part of "A Cartload of Cartograhpy", Tar-Palantir's article series looking at the history of maps and mapmaking! You can read part one, on ancient and medieval maps, here, and part two, on early modern mapping, here.



From the 18th century onwards, cartography pretty much becomes a case of increasing precision and accuracy, often in the service of imperial ambitions, and greatly helped by the invention of accurate marine chronometers in the later 18th century, making the determination of longitude possible. As states became more territorially-based, mapping and defining that territory became more important, so national mapping agencies begin to appear, charged with charting the homeland and its colonies in exacting detail, usually through thorough triangulation-based surveying. More sophisticated administrative structures also needed maps for things such as accurate taxation and governance. As machines started to become more involved and producing maps became easier, special-purpose maps, showing, say, the distribution of one kind of thing also became more common – say, regions where malaria was endemic. Fast forward to the current day, and maps are usually digitised, with all the possibilities that entails – cartograms, multiple layers of information and so on. Another big development is the use of contour lines and symbols for different kinds of land cover and features of interest – rather than representing a forest by drawing lots of little trees, modern maps will colour the area green or fill it with some sort of tree symbol. Rather than a little drawing of a town, there'll be a dot of the relevant size and style. And so on.

The important thing to think about here is that your map should reflect the technological level of the civilisation. If you're aiming for something, say, 18th-19th century, a hand-drawn look would be appropriate, but you're going to need to make sure it's pretty accurate. For a 20th-21st century look, you might want to consider using some GIS software (QGIS is free and fairly straightforward to create maps in – there are tutorials online) to make your map, for a digital look. And, of course, if you're aiming for something from the future, make sure to make your map look futuristic. In any case, make sure you include things like scale bars, meanings of abbreviations or foreign words, a colour and symbol legend if relevant, and so on.

At the same time, decorative maps are still very much a thing in this day and age, so a more old-style map would work, but you'd have to make sure you have a good in-universe reason for it being relevant.

That concludes our whistle-stop tour of cartographic history. Hopefully that's given you a few ideas for how you could make the map of your world feel more authentic – remember, the important thing is to create something that looks as if the culture and technology of your world could have produced it. So, if you're writing something faux-medieval, a clean digital map of the entire world is not a good idea; similarly, if you're more futuristic, a hand-drawn and wildly-inaccurate map is not really suitable. Happy mapping!



A Note On Projections

One other thing to bear in mind is the issue of map projections. It is, of course, impossible to accurately represent the surface of a sphere on a flat continuous 2D plane (of course, one solution to this is to present your map as a globe, but, depending on how you're aiming to present your map, that may not be feasible). There is, inevitably, a distortion of area, shape or position. Over the centuries, cartographers have come up with all sorts of different projections to minimise this issue in different ways, but which one is the 'best' really depends on your purpose. As stated above, the Mercator projection is great for regional nautical charts, but its very obvious and dramatic distortion of apparent area and shape at high latitudes means it doesn't work so well in depicting the entire globe. If you're aiming to produce a truly-accurate, modern-style map, therefore, you should investigate the range of projections available and pick one that suits – which one that is will depend very much on your particular requirements. Modern GIS software will easily allow you to change projections, so don't worry about having to work out the maths yourself.

However, if your map is meant to be from a pre-Enlightenment period, you can pretty much ignore this issue. The intrinsic inaccuracies in earlier maps mean that projection issues are negligible – it's only once you've got accurate positional data that projecting it properly becomes a real concern. If you do want to think about projections, though, the Mercator one is perhaps the easiest to use (hence its enduring popularity). This represents the surface of a sphere as if it were the unrolled surface of a cylinder, so lines of longitude become straight, parallel lines, much like lines of latitude (and that also shows you why it tends to infinity at the Poles). In other words, you can define a grid of parallel lines and use that to structure your map. But, if your map is hand-drawn based on hearsay from travellers, for instance, I really wouldn't bother...