Expanding cities: A grounded conceptual model that allows comparing systems of greenfield land development

When a city expands land use of the fringes has to be converted into urban land use. Surrounding land has a fixed position and is non-urban by definition. Within Western Europe, an intriguing variety of systems for this land conversion are being applied. Cross-national exchange of planning experience is of great interest, but the specific national context and (planning) systems make it difficult to fully compare countries. Nevertheless these systems to a large extent have the some objective (i.e. urban expansion) and deal with similar entities, such as power, ownership, land value and public facilities. This paper provides a basic model that represents the essence of this conversion of land use - its entities and its optional mechanisms - with the aim of contributing to a better cross-national understanding on instruments for city expansion. In addition, based on this understanding, we review some theories that may guide possible explanations for international variation.