Microsoft's Global Building Footprints data of Portugal

The growth of the Wildland-Urban Interface (WUI) underscores the need for accurate mapping to support effective wildfire risk management. One major obstacle is the lack of comprehensive national building footprint databases. Our study addresses that gap by developing a semi-automated, multi-criteria filtering framework aimed at enhancing the quality of global open-source building datasets, with a focus on Microsoft’s Global Building Footprints (MSB), applied to mainland Portugal. The proposed method incorporates regional adaptability and spatial analysis techniques—such as area-based thresholds and proximity criteria—using Portugal’s official Geographic Buildings Location Database (BGE) as a benchmark. To better represent residential structures, the framework systematically removes non-residential anomalies (e.g., industrial complexes, solar farms, transmission lines) through dynamically calibrated thresholds at multiple administrative levels, including municipalities and NUTS-2 regions. As a result, the filtering process reduced the original dataset from approximately 5.6 million to 3.0 million building footprints. The original and filtered datasets are available here.