Evaluation of Horizontal Geometric Accuracy and Area Differences of the Indonesian Topographic Base Map (RBI) Using GNSS RTK Measurements

Yastin David Batara (Study Program of Geomatics Engineering Technology and Surveying, Faculty of Civil and Earth Engineering, Politeknik Negeri Banjarmasin, Banjarmasin, Indonesia)
Muhammad Ikhsan (Study Program of Geomatics Engineering Technology and Surveying, Faculty of Civil and Earth Engineering, Politeknik Negeri Banjarmasin, Banjarmasin, Indonesia)

Eksakta : Berkala Ilmiah Bidang MIPA
Vol. 27 No. 04 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress

This study evaluates the horizontal geometric accuracy and area representation of the 1:50,000 Indonesian Topographic Base Map (RBI) using Global Navigation Satellite System Real-Time Kinematic (GNSS RTK) measurements as reference data. The study was conducted within a 29.937 ha area in Raden Village, Tanah Laut Regency, South Kalimantan Province, Indonesia. Horizontal accuracy assessment was performed using 12 boundary vertices identified from corresponding features in both the RBI map and field observations. Positional differences were quantified using the Root Mean Square Error (RMSE) and Circular Error at the 90% confidence level (CE90), while area differences were evaluated by comparing RBI-derived and GNSS RTK-derived boundaries. The results indicate RMSEx and RMSEy values of 11.638 m and 21.766 m, respectively, resulting in a CE90 value of 44.848 m. Although the evaluated RBI map satisfies the horizontal accuracy requirement for a Class 3 map according to BIG Regulation No. 6 of 2018, the CE90 value is close to the maximum allowable threshold of 45 m. In addition, the RBI-derived area underestimated the GNSS RTK-derived area by 9,332 m² (0.933 ha) or 3.12%.