Determination of Geoidal Undulation of Points Within the‎ Federal University of Technology, Akure, Using Geometric ‎Technique

  • Authors

    • Gafar Suara Department of Surveying and Geoinformatics, Federal University of Technology, PMB 704, Akure, Ondo State, Nigeria
    • Aminat O. Akinola Department of Surveying and Geoinformatics, Federal University of Technology, PMB 704, Akure, Ondo State, Nigeria
    • Adeola O. Tifase Department of Surveying and Geoinformatics, Federal University of Technology, PMB 704, Akure, Ondo State, Nigeria
    • Abdqudus A. Odeyinka Department of Surveying and Geoinformatics, Federal University of Technology, PMB 704, Akure, Ondo State, Nigeria
    https://doi.org/10.14419/m1y49p48

    Received date: February 10, 2026

    Accepted date: March 10, 2026

    Published date: March 14, 2026

  • DGPS; Geoidal Undulation; Geometric Technique; Gravimetric Data; Levelling.

  • Abstract

    This study determined the local geoidal undulation at thirty-one (31) points within the Federal University of Technology, ‎Akure, using a geometric method. Before data collection, a two-peg test was performed on the Leica automatic level, resulting in a ‎misclosure of 0.002 m, which verified the instrument’s suitability for precise levelling. Similarly, the Differential Global Positioning ‎System (DGPS) receiver was checked for optimal performance. Orthometric heights were obtained through geodetic levelling ‎observations using the height-of-instrument method, while ellipsoidal heights were measured with a Tersus DGPS receiver and ‎processed with Geomatics Office software. Geoidal undulations were calculated as the difference between the ellipsoidal and ‎orthometric heights. The resulting values were used to generate geoidal contour maps and a three-dimensional surface model in ‎Surfer 11 software, enabling visualization of the spatial variation and slope characteristics of the study area. Validation of the results ‎against previously established gravimetric geoidal undulations showed good agreement, with standard deviations and RMSE of ‎‎0.234 mm and 0.231 mm, respectively, demonstrating the reliability and accuracy of the geometric method for local geoid ‎determination. As demonstrated in this study, the geometric technique's efficiency, low operational cost, and minimal data ‎requirements make it a viable alternative for determining geoidal undulation in regions with similar terrain, particularly where ‎gravimetric data are unavailable or financially restrictive‎.

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  • How to Cite

    Suara, G., Akinola, A. O. ., Tifase, A. O. ., & Odeyinka, A. A. . (2026). Determination of Geoidal Undulation of Points Within the‎ Federal University of Technology, Akure, Using Geometric ‎Technique. International Journal of Advanced Geosciences, 14(1), 30-36. https://doi.org/10.14419/m1y49p48