Fancy name for a database with a map interface, like any of the county HERs (Historic Environment Record). The particular thing you can do with a GIS is it can hold shapes of things rather than just point locations, so you can see things like the location and shape of the scheduled area of a monument, as the MAGIC map used to (must find out what the link to that is now). Or in the case of the above research, the shape and location of 'pretend' 3D roundhouses.
Something is not right. This message is just to keep things from messing up down the road