Developing a more compact urban region through intensification and densification has been a fundamental and recurring theme in the body of research produced by the Neptis Foundation over the last 10 years. The Toronto-related Region Futures Study, undertaken for Neptis by the IBI Group and Metropole Consultants in 2002, describes the beneficial impact of increased intensification compared to business-as-usual greenfield growth. The research showed that directing growth to existing urbanized areas in appropriate forms, quantities, and locations can help reverse the decline of transit use and decrease the amount of rural land consumed by urban development.

Four years later, The Growth Plan for the Greater Golden Horseshoe (2006), the Province of Ontario's growth plan for the Toronto region, required all municipalities to accommodate growth by first looking inward to their already-urbanized areas before considering greenfield development. This principle is formalized through a residential intensification policy and target. However, Ontario municipalities had not been tracking residential intensification in a uniform manner before the policy and target were put in place, so there were no records of just how much intensification was already occurring.

The Neptis Foundation, working with the GIS and Cartography Office of the University of Toronto, decided to fill this gap in knowledge. The first task involved developing a method for defining the urbanized area of Ontario municipalities--the area within which new residential development could be considered to be intensification rather than greenfield development. This was done using satellite imagery. Second, the number of dwellings built over a particular period inside that boundary had to be determined; census data provided this information.

Although the process sounds straightforward, it took several years to develop and refine this approach to measuring intensification. However, the time was well spent, since the result was a reliable way to measure this crucial factor in urban development. Moreover, because Neptis researchers used data that are publicly available to municipal staff and researchers, this way of measuring intensification can be repeated for any city where high-quality satellite imagery and fine-grained census data are available. Neptis researchers have already gone on to apply the same approach to other cities in Canada as a way of comparing their patterns of growth and evaluating the effectiveness of policies to promote intensification.

This paper describes how the Province's intensification target works both in principle and practice through an examination of historical rates of intensification and takes a closer look at the concept of defining the urbanized boundary for the purposes of implementing and measuring Ontario's intensification target. Although the research is primarily directed to Ontario municipalities that are in the process of implementing the intensification target and developing a strategy for intensification, the findings of the research will interest all planners and policy-makers who are striving to achieve more compact and sustainable development.