# Scale (ratio)

The white protective helmet (right) serves as a benchmark for the viewer and reveals the enormous size of the construction machine.

In technology , photography, cartography and model making, a scale is the relationship between the size shown (for example the length of the route) and the corresponding size in reality.

## Enlargements

In some areas (mechanical engineering, electronics, macro photography) not only reductions but also enlargements are defined by specifying a scale. Here, for example, a scale of 2: 1 means that the construction drawing or the macro photo is twice as large as the real thing.

## True to scale and scale factor

To scale or scale is a figure or a model, if any route appropriate to the length results in the representation in the original same ratio. The tolerance for graphics corresponds to the usual drawing accuracy of 0.2 mm. A photo or a hand sketch , for example, is not to scale . In technical parlance , "to scale" usually means a less precise representation than one that is "true to scale".

In geodesy , minor differences in the scale of surveying networks or earth models are often treated in the form of a mathematical scale factor (usually referred to as µ ). Since it is always very close to the value 1 , it is often set as µ = 1 + m and the very small value m is referred to as the scale correction .

## architecture

In architecture, plans are used in a scale range from 1:10 (details) to 1: 1000 (overviews, external plans, site plans). However, some details are also drawn on a scale of 1: 1 to 1: 5 or, in extremely rare cases, even enlarged compared to reality.

In technical drawings, ISO 5455 gives suggestions for reductions and enlargements.