Electromagnetic fields modeling using GIS

Overhead transmission lines emit both electric and magnetic fields and they are called the extremely-low-frequency electromagnetic fields (ELF-EMF). Some researches believed that these fields would induce biological effects in human. However, research results are still inconclusive and further investigations are required before a definite conclusion can be drawn. However, it is important to have some measurement on the ELF-EMF of the environment for precaution. Following The International Radiation Protection ASsociation and The International Non-Ionizing Radiation Committee (IRPA/INIRC) Guidelines, a prototype system is set up using GIS software. Equivalent charges' method is used to determine the strength of the radition in the area nearby the overhead transmiton lines. The results are overlaid with the zoning map. Areas with radiation higher than the values suggested in the guidelines are identified. Results are conclusive with the Electricity Networks Ordinance in Hong Kong.