21. English Heritage conducted a geophysical survey in 2004. 22. Geophysical surveys were also carried out across much of the surrounding area and around Stonehenge Bowl.23. Archaeologists use a variety of tools when carrying out surveys, including geophysical survey and aerial photography. 24. A geophysical survey carried out at the end of 2005 revealed extensive remains in the area. 25. Geophysical surveys were carried out in 1987 and 1993 with exploratory trenches being dug in 1996.26. The data collected from a geophysical survey is analysed to draw meaningful conclusions out of that. 27. These include Airflite, a large defence contractor and Fugro the world's largest aerial geophysical survey company. 28. It began its investigations by conducting a large-scale geophysical survey of the former urban center of Gabii. 29. Mills'company, Geophysical Survey Systems, Inc ., made a radar system they used, which can search under ground. 30. The site saw no further work until a geophysical survey in 2006 and further excavations in 2007.
