There are two types of scales used in surveying.
Numerical scale:
1. Engineer’s Scale:
In engineer’s scale, the scale of a map or drawing is the proportion which every distance on the map or drawing bears to the corresponding distance on the ground.
Example: 1cm = 10m
This means, 1cm on the drawing represents 10m on the ground, the scale of the map is 10m to 1cm.
2. Fraction Scale:
The scale is also expressed by means of a vulgar fraction whose numerator is invariable unity. The fraction is called “Representative Fraction” or RF. It is, therefore, the ratio of map distance to the corresponding ground distance. In forming the representative fraction both numerator and denominator must be reduced to the same denomination.
Graphical Scale:
On a graphical scale, the units of measurement should always be stated.
Characteristics of a Good Scale are:
1. It should read to the greatest accuracy required.
2. It should be convenient to use.
