Scale (ratio)

For example, a drawing showing a new road in elevation might use different horizontal and vertical scales.

An elevation of a bridge might be annotated with arrows with a length proportional to a force loading, as in 1 cm to 1000 newtons: this is an example of a dimensional scale.

A town plan may be constructed as an exact scale drawing, but for larger areas a map projection is necessary and no projection can represent the Earth's surface at a uniform scale.

In general, the scale of a projection depends on position and direction.

(Generally, these may be mathematical sets and may not represent geometric objects.)