The Plane Table: Mapping by Drawing on Site

Every other surveying method records numbers in a book and turns them into a drawing later, at a desk, where a transcription error cannot be caught. The plane table skips the numbers entirely: the map is drawn ON SITE, at scale, with the ground in front of you. A board is levelled on a tripod and oriented so that north on the paper points north on the ground. Sight a feature along a straight edge, draw a ray, move to a second known station, sight the same feature again, and where the two rays cross is the feature's position — no angles measured, no trigonometry, no arithmetic at all. It dominated topographic mapping from the sixteenth century until the aeroplane, and its real advantage is still unbeaten: you can see immediately whether your map looks like the place you are standing in.