Identifying and characterising urban land use transformation processes using cadastral parcel geometries: A case study of Spanish cities

Cadastral vector data has become particularly important in urban studies due to its ability to accurately represent different urban realities, such as vulnerability assessment, densification processes and the development of simulation models. This paper proposes a framework for analysing changes in cadastral parcels in Spanish cities, identifying transformation process involving geometric and land use changes. Land use maps were obtained for two dates, one in 2022 and another in 2024, covering 48 Spanish cities and consisting of six categories: single-family residential, multi-family residential, industrial, commercial and office, others and undeveloped. The framework combines thematic and spatial analyses, intersection operations, graph construction, and geometric characterisation of changes through different spatial metrics of parcels. The results revealed three main processes affecting cadastral parcels: Aggregating, Subdividing and Non-impactful. These processes mainly affected on undeveloped land with varying geometric characteristics. Large parcels with complex shapes were transformed into simple and elongated parcels through Subdividing processes, while average-sized parcels with simple shapes were transformed into compact, more complex parcels through Aggregating processes. These results provide insights into how urban spaces are evolving not only in terms of land use change, but also through transformations in parcel geometry. This opens several future research lines grounded on the monitoring of cadastral data, such as urban densification studies, policy impact assessment and urban growth simulation models coupled with parcel transformation algorithms.