Planning where and how we live, work and play is fundamental to our economy, our environment, to our society and at its most basic, to our quality of life. The traditional terms of ‘town and country planning’ and ‘land use planning’ have for the most part now been taken over by ‘Spatial Planning’, since its emergence from Europe in the 1990’s. This new, broader, more cohesive and more collaborative planning methodology, particularly, when taken with the principles of informed decision-making, sustainability and balanced polycentric development endorsed at EU level [by the European Spatial Development Perspective, 1999 (ESDP), and EU Territorial Agenda, 2007] has lead ‘Spatial Planning’ and more specifically ‘Evidenced-Based Spatial Planning’ to arguably become a new or more likely, an evolving paradigm in the planning field. (Corepoint 2008)
The SPACEial NW project attempts to change attitudes and beliefs around the use of geographical information in making decisions. Evidence based spatial planning is not a new concept, it has been around since biblical times and this the chapter begins by examining how the relationship between data and planning has been evolving, i.e ‘...does policy guide research or does research guide policy...’ It also looks at how these earlier concepts have translated into planning and regional policy across both jurisdictions on the island. Finally, it reviews strategic planning documents relating to population distribution to set the scene for the analysis that takes place in Chapter 5.
 Polycentric development in ESDP refers to patterns of spatial concentration and dispersal. It challenges the notion of a single dominant centre or core growth zone/region in preference of multiple, connected, urban centres at the intra-regional level and a network of several well distributed global integration zones at inter-regional level. (Healey, 2001)