Land survey Training
Surveying is the technique, profession, art and science of determining the terrestrial or three-dimensional positions of points, the distances and angles between them. They are used to determine land boundaries for a variety of reasons, such as selling or buying a property, It is very important in the clarification of land boundaries, whether for residential or commercial use. They use the equipment, such as total stations, robotic total station, theodolites, GNSS receivers, retroreflectors, GIS and Surveying software etc.
What is a Total Station?
Total station is a surveying equipment combination of Electromagnetic Distance Measuring Instrument and electronic theodolite. It is also integrated with microprocessor, electronic data collector and storage system. The instrument can be used to measure horizontal and vertical angles as well as sloping distance of object to the instrument.
What are the capabilities of a Total Station?
Microprocessor unit in total station processes the data collected to compute:
Average of multiple angles measured.
Average of multiple distance measured,
Horizontal distance. Distance between any two points. Elevation of objects
All the three coordinates of the observed points.
Data collected and processed in a Total Station can be downloaded to computers for further processing.
Advantages of using Total Stations
The following are some of the major advantages of using total station over the conventional surveying instruments:
Field work is carried out very fast.
Accuracy of measurement is high.
Manual errors involved in reading and recording are eliminated.
Calculation of coordinates is very fast and accurate. Even corrections for temperature and pressure are automatically made. Computers can be employed for map making and plotting contour and cross-sections. Contour intervals and scales can be changed in no time.
Uses of Total Station
Electronic distance measuring (EDM) instrument is a major part of total station. Its range varies from 2.8 km to 4.2 km. The accuracy of measurement varies from 5 mm to 10 mm per km measurement. They are used with automatic target recognizer. The distance measured is always sloping distance from instrument to the object.
The electronic theodolite part of total station is used for measuring vertical and horizontal angle. For measurement of horizontal angles any convenient direction may be taken as reference direction. For vertical angle measurement vertical upward (zenith) direction is taken as reference direction. The accuracy of angle measurement varies from 2 to 6 seconds.
This instrument is provided with an inbuilt microprocessor. The microprocessor averages multiple observations. With the help of slope distance and vertical and horizontal angles measured, when height of axis of instrument and targets are supplied, the microprocessor computes the horizontal distance and X, Y, Z coordinates. uThe processor is capable of applying temperature and pressure corrections to the measurements, if atmospheric temperature and pressures are supplied.
Electronic display unit is capable of displaying various values when respective keys are pressed. The system is capable of displaying horizontal distance, vertical distance, horizontal and vertical angles, difference in elevations of two observed points and all the three coordinates of the observed points.
Each point data can be stored in an electronic note book (like compact disc). The capacity of electronic note book varies from 2000 points to 4000 points data. Surveyor can unload the data stored in note book to computer and reuse the note book