The landscape mapping conducted by the NIBIO is based on a method developed by the US Forestry Service, adapted to Norwegian conditions.

A landscape feature in the landscape reference system is a continuous area (polygon) with the same attributes assigned according to the classification criteria defined in the naitonal landscape reference system.

The three-dimensional classification of the landscape is based more on a multidisciplinary understanding and holistic evaluation, than on traditional science and cartography. Studying six main components of the landscape is important in three-dimensional landscape mapping, while the relative importance of individual components varies between the different landscape regions. The main components are: major landforms; geological composition; water and waterways; vegetation; agricultural land and buildings.

The reference system consists of a national map dividing the country in 45 landscape regions and 444 sub regions. Furthermore, 10 agricultural regions have been classified, emphasizing common preconditions for agriculture.