Archaeologists often divide earthworks into positive and negative types: positive being those which are built up of archaeological material, such as banks or mounds; negative being those which are cut into the surrounding earth – a good example of negative earthworks are the deep channels left by many years of human and animal traffic along roadways in medieval settlements  - these are known as ‘hollow ways’.  Most monuments and sites, such as prehistoric burial mounds or deserted medieval villages, are a composite of negative and positive earthworks.  Archaeologists can map and record earthworks using aerial photography and topographical survey.  Whereas most people would be able to identify a simple round barrow or the bank and ditch defences of an Iron Age hillfort, complex earthworks are often confusing to view at ground level alone.  A mass of ‘humps and bumps’ can seem to lack form and pattern, especially when they represent a number of different periods of activity, and are possibly not in a good state of preservation.  However, by systematic measurement and recording, it is almost always possible to ‘make sense’ of these features.  

 

Accurate maps of earthworks can be used to reconstruct the plans of villages and field systems, and help archaeologists decide where to excavate for more information. Earthworks in ploughed fields are sometimes so degraded that they are hard to see, but can be recorded with careful painstaking work. At some sites, earthworks surround surviving buildings, such as a church or farmhouse which may be all that remains of a former village. Earthworks sometimes cover many miles of countryside, revealing whole landscapes of ancient fields, trackways and settlements.