A lecture on what maps leave out

Professor Lindqvist: Good morning. Last week I suggested that every map is an argument, and several of you looked at me as though I had said something faintly indecent. So let me defend the claim. A map is not a window onto the world; it is a decision about what deserves to be remembered. Consider the humble coastal chart of the eighteenth century. Its makers did not draw rocks because rocks exist. They drew the rocks that had sunk ships, which is to say they drew a history of misfortune and called it geography.

Professor Lindqvist: Now, the interesting part is what these charts leave blank. A white space on a map is rarely an absence of knowledge. More often it is an absence of interest. The surveyor of a certain northern estuary, whom I shall call Mr Pellham, spent three summers measuring its sandbanks, and then, quite deliberately, drew the inland marshes as a pale, featureless wash. The marshes were well known to every local fisherman. They simply earned no money for his patrons, and so, on paper, they were not there.

Professor Lindqvist: You might object that this is merely a matter of scale. A map as large as the territory would be useless, as the old joke goes, and omission is the price of usefulness. I accept that, up to a point. But there is a difference between a simplification and a silence, and critical cartography begins with learning to tell them apart. A simplification can be reversed: give me a larger sheet and I will add the detail. A silence cannot, because nobody ever collected the detail in the first place.

Professor Lindqvist: Let me offer a modern parallel, since I'm told that anything older than a decade strikes you as antique. Navigation applications now choose routes for millions of drivers, and they quietly favour wide, fast roads. Residents of a narrow lane in a hill town I visited were bemused to find their street suddenly crowded with lorries. Nothing had changed on the ground. The lane had merely been promoted, by an algorithm, from an afterthought to a shortcut, and nobody had asked those who lived there whether they wished to be a shortcut.

Student: Professor, doesn't that make every map a kind of lie? If it's all selection, how can we trust any of them?

Professor Lindqvist: A fair question, though I would resist the word lie. A lie requires an intention to deceive, whereas most selection is made out of habit, convenience, or the wishes of whoever is paying. The remedy is not distrust but literacy. Ask who made the map, for whom, and what they would have lost by including the thing that is missing. Do that, and a map stops being a verdict and becomes what it always was: a very good piece of evidence, from a witness with an interest. And be wary of any map that looks perfectly confident.