Methodology
1)Determination of EDM zero correction:
The approach for determining the zero correction of an EDM was to divide a long straight line into parts. The approach for determining the zero correction of an EDM is to divide a long straight line into parts. The appropriate sections were measured, as well as the long line, and the zero correction was computed.
2)Setting out of base line:
A theodolite and ranging poles are used to set out the baseline. set up the theodolite on the starting point after a pillar has been placed. The direction is defined by pointing the theodolite in the predetermined direction. place the beacons at the two ends of the baselines. Use the EDM work in conjunction with theodolite and the battery fixed. It has to be then set over pillar and level the reflector too. After that, the following operation should be carried out
The height of EDM instrument and reflector’s height are measured with line tape and record in the field book. The intension is to determine the slope correction to bring the measured slope distance to horizontal distance. Reflector is then sighted, the prism’s center is bisected, and the theodolite’s vertical and horizontal movement is clamped. Checks for a battery and turns on the instrument’s on/off switch to make the signal.
The display reads 0000, which means the instrument is ready to use. The “MEASURE” knob is softly touched to start the measurement. The distance measurement is completed automatically in less than 5 seconds, during which time points on the digital display flash and the measured distance is displayed.
3)EDM Measurement:
To measure any distance, you simply compare it to a known or calibrated distance for example by using a scale or tape to measure the length of an object in EDM’s the same comparison principle is used the calibrated distance in this case is the wavelength of the modulation on a carrier wave.
The advent of EDM equipment has completely revolutionaries all surveying procedures and resulted in a change of emphasis and techniques, by reason of the fact that distance can now be measured quickly and accurately, regardless of terrain condition.