The Role of Open-Source Data in Disaster Preparedness and Response. A Case Study on Flood Impact in Local Communities

Abstract. Flooding remains one of the most destructive natural hazards globally, resulting in severe social, economic, and infrastructural impacts. This study investigates the role of open-source geospatial tools and community-contributed data in enhancing disaster preparedness and response, using the Jakande Housing Estate in Lagos, Nigeria as a case study. The methodology integrates multi-temporal analysis of high-resolution satellite imagery over a six-year period to detect land cover changes and assess flood risk dynamics. Initial analysis revealed significant data gaps within OpenStreetMap (OSM), prompting the initiation of a targeted mapping campaign via the Humanitarian OpenStreetMap Team (HOT) Tasking Manager. This initiative mobilized volunteers to update critical geographic features. To complement remote mapping efforts, in-situ data collection was carried out using the Open Data Kit (ODK), capturing real-time information on infrastructure conditions and displacement patterns. Spatial analyses, including change detection and overlay techniques in QGIS, revealed that over 40% of residential zones within the study area are located in high-risk flood-prone zones, with essential facilities, such as police stations and commercial clusters, also affected. The findings underscore the value of integrating remote sensing, open-source geospatial data, and participatory mapping approaches to enhance situational awareness and support evidence-based emergency response planning. Nonetheless, the study faced limitations due to variability in spatial resolution and restricted access to high-quality spectral data. Future research should explore the integration of higher-resolution imagery and predictive flood modeling to further improve impact assessments and inform long-term resilience strategies.