Automated and Comprehensive Quality Assessment of Nationwide Aerial LiDAR Data: Insights from the LiDAR-ITA Project

Abstract. National LiDAR programs are increasingly adopted worldwide to support land management, infrastructure planning, and environmental monitoring. Italy launched its most extensive airborne LiDAR operation in July 2025 as part of the Integrated Monitoring System (SIM) project, funded by the National Recovery and Resilience Plan (PNRR). This effort represents the most extensive airborne LiDAR campaign ever conducted in the country, covering over 302,000 km², including coastal zones and major islands. The acquisition plan is designed to ensure a minimum point density of 10 points/m² and produce high-resolution DTMs and DSMs at a 0.25 m grid spacing. Given the unprecedented spatial and data volume, a robust, standardised, and fully automated quality assurance framework is essential. This paper presents the methodology used to evaluate geometric consistency and spatial accuracy across the national dataset. Congruence between overlapping flight strips is assessed by automatically extracting 100 × 100 m patches at regular intervals and computing point-to-point distances and cross-section profiles to detect horizontal and vertical discrepancies. Plano-altimetric accuracy is further evaluated through comparisons with terrestrial laser scanning (TLS) data collected in dedicated control areas, where robust plane fitting enables rigorous three-dimensional error estimation. Results from two control areas acquired with different sensors demonstrate the robustness and scalability of the proposed automated framework. The presented approach provides a reliable foundation for delivering high-precision national LiDAR products and offers a framework applicable to future large-scale geospatial acquisition programs.