Scholarly record
HOW DOES THE DATUM POINT LOCATION AFFECT THE ACCURACY OF THE ADJUSTED BENCHMARK HEIGHTS IN A PRECISE LEVELING NETWORK?
Abstract
It is well established that the farther a benchmark is from the datum point in a leveling network, the greater its standard error of adjusted height tends to be. To explore the optimal datum point location for minimizing height uncertainty, we performed 11 separate adjustments of the Second Bulgarian Leveling Network. Each adjustment used a different nodal benchmark as the datum point. While all adjustments yielded identical benchmark elevations and the same mean adjustment error of 2.14 mm/km^0.5, the sum and average of the standard errors of the adjusted heights varied. The lowest total standard error was obtained when the datum was set at Kazanlak, located near the network-s mass center. This adjustment produced the lowest average standard error: 21.83 mm. In contrast, placing the datum at peripheral points significantly increased uncertainty. For example, the average standard errors were: - Sofia: 26.2 mm - Tutrakan: 26.4 mm - Dospat: 26.7 mm A Kruskal-Wallis H test comparing the medians of the standard error samples across adjustments rejected the null hypothesis of equal medians at the 90% confidence level. This confirms that the datum location has a meaningful effect on the distribution of benchmark standard errors. Therefore, datum point placement must be considered when evaluating the accuracy of height adjustments, especially when estimating vertical crustal movements in geodynamically stable regions such as Bulgaria.
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References6
Caspary W. F., Concepts of Network and Deformation Analysis, Monograph 11, Third Edition, School of Geomatic Engineering, The University of New South Wales, Australia, 2000, ISBN 0-85839-044-2
Halim Setan H., Singh R., Deformation Analysis of a Geodetic Monitoring Network, Geomatica, Volume 55, Issue 3, 2001, pp. 333-346, ISSN 1195-1036, DOI: 10.5623/geomat-2001-0039
Gospodinov S., Peneva E., P. Penev, A specific approach to least squares adjustment of the state levelling network, 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Albena, Bulgaria, 2020, DOI: 10.5593/sgem2022/2.1/s09.20
Belyashki, T. A new map of the recent vertical movements of the Earth�s crust on the territory of Bulgaria. Geodezia, kartographia, zemeustroistvo. 2012, 3-4, 3-5 (in Bulgarian).
Nevada Geodetic Laboratory GPS Networks Map, https://geodesy.unr.edu/NGLStationPages/gpsnetmap/GPSNetMap.html (visited on 06.05.2025)
Bagdonavicius V., Kruopis J., Nikulin M.. Nonparametric tests for complete data, John Wiley & Sons, Inc., 2011, ISBN 978-1-84821-269-5
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