Accuracy Assessment of Topographic Maps Produced from Total Station and GNSS Surveys for Campus Mapping at Ahmadu Bello University

Institutional campus mapping provides foundational spatial data for facility management, master planning, and infrastructure maintenance at Nigerian universities. This study conducts an accuracy assessment of topographic maps produced through Total Station and GNSS surveys across the Main Campus of Ahmadu Bello University, Zaria, Kaduna State. A control framework established through differential GNSS observations serves as the reference datum, and detail surveys are conducted separately using Total Station traversing and RTK GNSS. The two resulting topographic datasets are compared against the control framework, and accuracy metrics including root mean square error, maximum positional error, and 95th percentile error are computed for planimetric and height components. Buildings, roads, utility lines, and vegetation boundaries are evaluated as separate feature categories. Results indicate that Total Station surveys achieve marginally higher planimetric accuracy, with RMSE below three centimetres, compared to RTK GNSS with RMSE of approximately five centimetres. However, RTK GNSS affords significantly faster data collection for open terrain features. Hybrid survey strategies combining both methods are recommended for campus mapping projects, with Total Station reserved for congested built-up areas and RTK GNSS applied to open spaces. The study contributes to survey methodology selection criteria relevant to university estate departments across Nigeria. Keywords: topographic mapping, Total Station, RTK GNSS, accuracy assessment, Ahmadu Bello University.