Heterogeneity of urban manufacturing – a statistical analysis of manufacturing companies in three German cities

The paper delves into the normative Productive City concept as outlined in the New Leipzig Charter, focusing on urban manufacturing's heterogeneity. We define urban manufacturing as manufacturing sectors located in proximity to housing. Urban manufacturing is analyzed based on sectoral (company data classified by NACE codes into 13 types of material industry) and spatial data, considering the distance to priority roads, supply areas, and land-use categories. The methodology is applied to Bochum, Gelsenkirchen, and Herne in the Ruhr area, utilizing 2018 data to identify material industry locations. We highlight differences between central and accessible, and more dispersed sectors in three groups. Group I, including other consumer goods, food products, clothing goods, and repair services, is predominantly located in central and mixed-use locations, suggesting these types could be preserved or developed by urban planners under the Productive City framework. However, there is a clear need for commercial and industrial spaces for emitting industries (Group II) to fully realize this concept. Construction industries (Group III) are often found in residential areas due to off-site activities. Challenges arise in historical industrial cities especially in integrated areas where existing zoning regulations and grandfathering rights restrict changes in manufacturing types or expansions near residential zones.