Closing the Digital Gap in Nigerian Land Records: An Open-Source QGIS Plugin for Cadastral Survey Archiving and Spatial Management

Chukwuma Samuel Ugwu , Joe Odeh

Secure, retrievable cadastral records are foundational to land tenure security and effective land administration, yet most private cadastral surveying firms in Nigeria maintain survey records exclusively on paper, a structural limitation that prevents spatial querying, concurrent access, and long-term integrity verification across the 50-year archival period required by the Survey Co-ordination Act. This paper presents the Survey Management System, a free and open-source QGIS plugin connected to a PostgreSQL/PostGIS spatial database, which connects the AutoCAD drafting workflow already standard in Nigerian cadastral practice to a structured digital archive without requiring practitioners to change how plans are drawn. The system implements bearing-and-distance traverse computation conforming to the Nigerian Survey Regulations 1:5000 precision standard, role-based access control structured around the principal surveyor hierarchy, MD5 cryptographic document integrity verification, and automatic detection of boundary conflicts with neighbouring cadastral records. Its principal contribution to digital land administration adoption is an automated DXF import engine that reads beacon coordinates, boundary polylines, traverse annotations, and plan metadata directly from AutoCAD files, eliminating the manual data re-entry identified as the main barrier to digital uptake in private firms. The engine exploits the finding that the Boundary LWPOLYLINE in Nigerian AutoCAD survey plans encodes the correct traversal order in vertex sequence. Validation on production plans from a licensed firm in Imo State demonstrated sub-centimetre traverse closure accuracy (precision ratio 1:16,240 against a regulatory minimum of 1:5000) and complete metadata recovery. Record retrieval time fell from approximately 20 minutes to under 2 seconds; spatial proximity queries, previously impossible under the paper system, complete in under 5 seconds. The plugin is freely available with no commercial licensing requirement and exceeded 255 downloads across 20 countries within its first month of release.