Electromagnetic location combines many advantages and facilities for obtaining information from underground that are not available from any other technique or combination of techniques.

• It can search an area from the surface to locate buried lines.
• It can trace and identify a target line.
• It can trace and identify sewers or other non-metallic ducts or pipes to which there is access; it can locate blockages and collapses.
• It can measure depth from the surface.
• It can monitor the progress of ‘No Dig’ tools and instruments.
• The technology can be used to provide data to steer equipment or tools both above ground and below ground, or on the sea bed.
• It can find some types of cable fault, monitor pipeline coating condition and locate water leaks in plastic pipes.
• It can pinpoint the position of joints in iron gas pipes.
• The equipment is portable.
• The equipment is easily handled and is successfully used by workers.
• The technique works in all soil conditions; even underwater.
• The component parts of the technology are low Sufficiently low cost to be purchased by small contractors or issued on a large scale by regional or national organisations.
• The technology exists today.

The wide variety of functions and applications requires just three basic building blocks:

• a signal generator or transmitter to apply a signal to a buried line.
• a small self-contained transmitter suitable for inserting in drains or ducts.
• a handheld receiver to locate the signals from the transmitters or to locate signals occurring ‘naturally’ on buried lines.