Evaluating land policy outcomes in emerging built urban form. A covariational geospatial approach

Urban form is a key concern for sustainable urban development and climate change adaptation. Therefore, it has become a focus for policymakers and planners in the past decades. While many national governments implement land policies to pursue specific objectives, the actual outcomes in built urban form often remain scarcely evaluated, thus challenging the effectiveness and legitimacy of these policies in pursuit of urban sustainability objectives. In this contribution, we therefore evaluate anticipated outcomes of land policies by quantifying the emerging built urban form under these policies through a covariational approach. The French-German border-region serves as a study area due to its economic and demographic homogeneity, while fundamentally different land policies are pursued. A fine-grained geospatial data model representing the evolution of urban form is set up containing harmonised building, parcel and street network data. Based on this, building types, development blocks, ages and relative location through accessibility are delineated. The model is used to trace anticipated outcomes of key policy changes in the emerging urban form of the two countries. This assessment shows significant variance in measurable outcomes of specific land policies of the two countries, in time and by policy that can be linked to different initiatives of implementing policies in Germany and France, prompting a stronger debate of how land policies generate effects.