Land surveyors use different equipment for surveying such as:
- Total stations/topographic robotic stations
- 3D scanners also called laser scanners or lidard scanners
- Surveying prism, surveying rod and PK (landmark nail)
Total Stations Vs Robotic Stations
A total station and a robotic station perform the same role and are almost the same thing. A total station that is not robotic requires someone behind the device to follow the prism while the robot automatically follows you. So, robotic stations require a surveyor and non-robotic stations (total stations) require a surveyor and a rod holder.
Essentially, 3D laser scanners are used to have a perfect digitized study of the surrounding terrain and objects. With an excellent 3D survey, planning the budget and schedule of a construction project will be much easier. 3D scanner technology uses a laser beam sent through a rotating mirror. The scanner analyzes the interference position of each point/target and then integrates it into a point cloud. Then software analyzes all the readings (point cloud) which contain several million coordinates with incredible precision of the order of a millimeter.
Prism and rod for surveying
Surveying prisms are attached to the surveying rod and are used as a focal point to gather distance information to measure the change in position of a target believed to be moving. Here is a picture of a prism.
The surveying rod is used to keep the prism perfectly perpendicular to the location where you want to make a measurement.
How long is a rod in surveying?
The length of a rod varies from 1.55m to 2.6m, but some go up to more than 4m. In the latter case, it is very practical in excavation because the holes are very low and this gives the device a better chance of seeing the prism
The PK is a surveying nail which serves as a reference on the ground. It has a notch on the head to put the tip of the rod.