Units of Measurements
Four kinds of units of measurements used in plane surveying
a) Horizontal distance
b) Vertical distance
c) Horizontal angle
d) Vertical angle
Note:
A. Linear Measurements
- The unit of measurement of distance is meters and centimeters (metric units)
- The units of measurements of area are sq. meters, sq. centimeters, hectares and sq. kilometers
- The units of measurements of Volume are cubic meters, cubic centimeters
B. Angular Measurements
- An angle is the difference in direction of two intersecting lines.
- The radian is the unit of plane angle.
a) Sexagesimal System
1 circumference = 360° (degree of arc)
1 degree = 60’ (minute of arc)
1 minute = 60” (seconds of arc)
b)Centesimal System
1 circumference = 400g (grads)
1 grad = 100c (centigrads)
1 centigrad = 100cc(centi-centigrads)
c)Hours System
1 circumference = 24h(hours)
1 hour = 60m(minute of time)
1 minute = 60s (seconds of time)