Work out plane table scale instantly with clear inputs, formula shown and shareable results.
Map scale is a pure ratio, so one centimetre at 1:1000 represents 1000 centimetres, or ten metres, on the ground. Working the relation the other way gives the plotting distance for a measured ground length. Areas scale with the square of the denominator, which is why a 1:1000 map covers a millionth of the ground area per unit area of paper.
Ground distance
Ground m = map cm x scale denominator / 100
Plotting distance
Map cm = ground m x 100 / scale denominator; area factor = denominator²
Ground m = map cm x scale denominator / 100. Map scale is a pure ratio, so one centimetre at 1:1000 represents 1000 centimetres, or ten metres, on the ground.
About 0.2 mm on paper, which is the limit of a sharp pencil and the eye. At 1:1000 that is 0.2 metres on the ground, so surveying to millimetres for a plotted map is wasted effort.
This calculator takes 3 inputs: Map scale denominator, Distance measured on the map, Ground distance to plot. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.