What is GIS?
GIS stands for “Graphic Information System” which essentially uses a computer-based map to identify where features were found, what they are, etc. – i.e. your historic environment record .
This is called “modelling” as you are drawing a model of how things may have looked and been laid out during the period being investigated.
From a single find (perhaps parts of a beaker near the remains of a wall in a field that has existed a long time) it is possible to begin to envisage more of the site during a particular period according to the date of the finds. For example whether it was a house, a farm, the edge of a town, how many people may have lived or worked there and the extent of the site (through tithe maps and censuses).
GIS is changing the face and direction of Archaeology .
GIS uses “layers”. Just as you might trace over the outline of a country or town using tracing paper over a map, the same is the done with GIS.
You may want one layer of tracing paper for the country’s outline…
Another for the contours of a hill or surrounding area…
Another for the transport systems (road, rail, bus-routes, etc.), another for the building outlines, another for where the mains power, water and gas come in…each of these pieces of tracing paper is a “layer” in GIS.
In the last case, the “REAL WORLD” might be an OS (Ordnance Survey) map or even Google map.
CIfA (the Chartered Institute for Field Archaeology) have policies and procedures surrounding any ‘prospecting’ which include GIS, Remote Sensing, Drone use, etc. . These policies and procedures are applicable in the wider world of landscape investigation .