UrbanFormAnalyzer: an open-source workflow to derive orientation-specific building envelope attributes from cadastral data

Detailed building-envelope information is essential for robust urban-scale energy performance analyses. However, national energy certificate databases in Spain and other countries often lack key attributes such as orientation-specific external perimeter measurements and glazing ratios. This paper introduces UrbanFormAnalyzer, an open-source Python library developed with QGIS, which automatically derives orientation-specific external perimeters and additional envelope descriptors from cadastral geometries. The workflow establishes a standard input structure to support integration with varied cadastral sources. As an example, we offer an adapter for the Spanish Cadastre that downloads and preprocesses their KML files, converting them into the required format. The spatial processing stage then calculates the perimeters by cardinal orientation, distinguishing exposed from adjacent walls. To illustrate a potential downstream application, the enhanced datasets are matched with national energy certificates to explore the estimation of orientation-specific glazing ratios, where such data are available. While predictive accuracy remains limited, the case study highlights how UrbanFormAnalyzer could support the creation of reproducible and harmonized building envelope data suitable for a range of analytical applications, including large-scale energy modeling, planning, and renovation assessment.