Map Liberator: An open-source tool for recovering spatial epidemiological data from static situation reports

Abstract Background Much of the world’s historical and current epidemiological data remains locked in static formats, such as PDF situation reports or image-based surveillance bulletins. Recovering this data for spatial analysis typically requires proprietary software (e.g., ArcGIS) or laborious manual entry, which is prone to transcription errors. Methods I developed Map Liberator, an open-source application built in R and Shiny. It provides a split-screen digitisation interface that allows users to overlay static reference maps alongside interactive administrative boundaries. The tool uses a stateful rendering engine to manage complex geometries (up to Admin Level 3) and facilitates the extraction of binary, numeric, or qualitative data directly into a structured, machine-readable format. Results I demonstrate the tool’s utility by digitizing Lassa Fever surveillance data from Nigeria (2018-2025). The tool successfully aligned static situation reports with official Local Government Area (LGA) boundaries, allowing for the rapid recovery of binary presence/absence data that was previously inaccessible for computational modelling. Conclusions Map Liberator provides a low-barrier, cost-effective solution for field epidemiologists and researchers to liberate spatial data from static reports, supporting the principles of FAIR (Findable, Accessible, Interoperable, Reusable) data in global health.