Scale Drawings

Understanding Scale Drawings

  • Scale drawings are a representation of an object or space using a ratio or fraction to scale down real world distances.
  • The scale used in the drawing is noted alongside it, typically in the form of 1:n, indicating that every 1 unit on the drawing corresponds to n units in real life.
  • Scales can also be given as equivalent lengths, such as 1 cm to 1 m, meaning 1 cm on the drawing equals 1 metre in reality.

Drawing to Scale

  • To draw something to scale, use the given scale factor to determine the size of your drawing. For example, if the scale is 1:100 and the real world object is 500cm long, the length of the object on your drawing would be 500 ÷ 100 = 5cm.
  • Distances on scale drawings should always be measured using a ruler with the appropriate units (mm, cm, etc.).
  • All parts of a scale drawing should be at the same scale for it to accurately represent the real world object or space.

Working with Scale Drawings

  • To interpret dimensions on a scale drawing, you must multiply the measurement on the drawing by the scale factor. For example, if the scale is 1:100 and a length on the drawing is 8cm, the real world length is 8 × 100 = 800 cm.
  • If you are provided with a scale in the form of 1 cm to n m, remember that 1 m is equivalent to 100 cm.
  • Mistakes often occur when the scale factor’s units are mixed up, such as 1 cm on the drawing equalling 1 m in real life. Always ensure you convert the units appropriately.

Working with Maps

  • Maps are a common application of scale drawings. The scale on a map indicates how the distances represented on the map relate to actual distances in the real world.
  • Map scales are typically large scale factors like 1:50000, where 1 cm on the map represents 50000 cm (or 500m) in real life.
  • Using a ruler and the scale, you can calculate real world distances based on measurements taken from the map. Conversely, you can calculate the size of a drawing to be made based on real world distances.
  • Carefully read grid references on maps as they can help in accurately determining locations.