Geography

Cartographic scales


In a map, we call the cartographic scale the relationship between the dimensions presented on the map and the real object it represents.

These dimensions should always be taken in the same unit.

The form of representation is as follows:

Scale = measured on map : measured on the actual object

or

Scale = measured on map / measured on the actual object

For example, if a map displays the scale 1:50means that 1 cm on the map is equivalent to 50 cm in the actual area.

If we want to indicate that each centimeter of a map represents 1 meter in the real area, we use the scale 1:100 or yet 1/100. Note that we have converted 1 meter to centimeters (100 centimeters), as both measurements must be in the same unit.

The scale indication is usually shown on the map or drawing shown. For example:

The scale can also be represented in graphical form, which is made unit by unit, where each segment shows the relationship between the longitude of the representation and the actual area. For example, note the following graphical scale.

This representation is indicating that each segment of the graphical scale presented is equivalent to 400 kilometers of real area.

Regarding the size of the representation, we can use the following classification:

  • Natural scale: Numerically represented as 1: 1 or 1/1. Occurs when the physical size of the object represented in the plane coincides with reality.
  • Reduced scale: when the actual size is larger than the represented area. It is usually used in maps of territories or housing plans. Examples: 1: 2, 1: 5, 1:10, 1:20, 1:50, 1: 100, 1: 500, 1: 1000, 1: 5000, 1: 20000.
  • Enlarged scale: When the graphic size is larger than the actual one. It is used to show minimal details of a particular area, especially small size spaces. Examples: 50: 1, 100: 1, 400: 1, 1000: 1.