Most of the South African coastline was investigated as part of the NSIP studies. The parts that were not investigated were areas within 50 km of the coastal cities and the coastline of the previous homeland areas of the Ciskei and Transkei. The studies, undertaken by consultants contracted by Eskom, were predicated on a number of criteria, such as demography (existing population densities), ecological sensitivity, geology, the characteristics of the coastal area and the tides and wave action and seismicity, amongst others.