Land surveying is a precise science that requires high-quality equipment to achieve accurate results. The essential tools used by land surveyors enable them to measure angles, distances, and elevations with pinpoint precision. Having the right gear and knowing how to use it properly allows surveyors to map boundaries, construct infrastructure, and support engineering projects. This guide covers the essential land surveying equipment for accurate and reliable surveying.
Levels are used to determine relative elevations and heights. They work by calibrating a precisely horizontal line of sight. The main types of levels used in land surveying are dumpy levels, automatic levels, and digital levels.
Dumpy levels are simple, rugged, and reliable optical instruments. They consist of a telescope mounted within a pair of rings that are levelled using foot screws. The surveyor aims the telescope at a level staff to measure height differences and mark elevations. Dumpy levels provide accurate level sights up to 300 feet. They are inexpensive and don’t require batteries or electricity.
Automatic levels use a compensator to self-level the line of sight. The surveyor centres the bubble, and the compensator does the rest, speeding up levelling. Automatic levels allow fast levelling for longer sight distances over 500 feet. They are more expensive but very convenient for repetitive levelling tasks.
Digital levels are precise instruments that use electronic linear encoders to provide elevation data quickly. They allow the surveyor to take measurements, record data digitally, and transfer it to CAD software for mapping. Advanced digital levels can even auto-track a prism for continuous elevation profiling. They are the fastest and most accurate option but also the most expensive.
Theodolites precisely measure angles in both the horizontal and vertical planes. They are more sophisticated descendants of the compass. Theodolites consist of a telescope mounted within two graduated circles calibrated for angle measurement.
Optical theodolites are read manually by the surveyor. They incorporate spirit levels, vertical arcs, horizontal circles, and micrometres for high-precision angle measurements. Optical theodolites are rugged and capable but slow to read.
Electronic theodolites accelerate measurement by using linear encoders to produce digital angle readouts. This allows quick point-and-shoot style measurements. Data can be downloaded into field computers and software. Electronic theodolites are efficient but require battery power.
Robotic theodolites are motorised instruments that can automatically align on targets. They use servo-motors to turn to predetermined angles or track prisms for continuous surveying. Robotic theodolites increase speed and can even be operated remotely. They are the most advanced angle measurement tools available.
Total stations are electronic theodolites integrated with electronic distance meters (EDM) to measure angles and distances. This allows the surveyor to calculate precise coordinates for target points.
Reflectorless Total Stations
Reflectorless total stations use laser EDMs to measure distances to any object without a prism. This allows faster targeting of trees, buildings, and other objects with reasonably accurate results. The helpful range is around 500 feet.
Prism Total Stations
Prism total stations offer the highest accuracy by measuring distances to prisms with specialised coatings that precisely reflect the EDM beam to the instrument. With prisms, distances up to 1 mile can be measured with a precision of a few millimetres.
Robotic Total Stations
Robotic total stations combine automated servo motors, reflectorless measurement, and computer interfaces. This allows one surveyor to control the instrument from prisms around the site remotely. Robotic total stations are the most technologically advanced option.
Global Navigation Satellite Systems (GNSS)
GNSS technology, like GPS, allows surveying measurements to be referenced to geographic coordinates. Handheld GNSS units are commonly used for surveying and mapping.
Real-Time Kinematic (RTK) GNSS
RTK uses a base station receiver at a known location to transmit correction data to roving units for precise positioning accurate to a centimetre level. This provides highly accurate coordinate data collection.
Static GNSS Surveying
Static surveying involves occupying a point for an extended time to collect data. The long observation period allows high accuracy with post-processing. It is suitable for fixed control points and geodetic networks.
Survey-Grade GNSS Receivers
Survey-grade receivers feature dual multi-channel tracking for reliable use under tree canopy and in challenging conditions. They typically allow integration with robotic total stations and advanced software.
Measuring Tapes and Wheels
While electronic distance measurement dominates today, the simple measuring tape and wheel can still be helpful survey tools. Steel tapes allow direct linear measurement for shorter distances or rough checks. Measuring wheels quickly measure longer traverses along the ground.
Data collectors are field computers that store measurement data from electronic land surveying equipment. They interface with total stations, GNSS receivers, and levels to capture and process field measurements. Data collectors streamline the transfer of surveying observations into CAD software.
Advanced surveying requires high-precision equipment to gather accurate spatial data. The newest digital instruments allow faster measurements and more accessible data handling than older manual techniques. But both traditional and cutting-edge equipment require skilled operators to utilise them effectively. With quality gear and proper training, today’s land surveyors harness powerful mapping tools.