| Summary: | Borobudur is one of the world heritages that should be preserved.
Maintaining the temple could be done by monitoring the stability of the soil and
construction structure of the temple. Geodetic method has been employed to monitor
the vertical stability of the Borobudur temple by measuring vertical position of the
monitoring network points periodically using waterpass (leveling). In 2012 instead
of using waterpass, trigonometric leveling was applied to measure the height
differences between points with some modification on the network geometry. The
instrument and network geometry changes could affect the precision of the observed
point. This research focused on analyzing the quality and strength of figure of the
trigonometric leveling network observed using waterpass and Total Station and also
analyzing the vertical displacement at these networks.
This study used leveling network data observed in 2011 measured using
automatic waterpass Leica Sprinter M-100 and trigonometric leveling data in 2012
measured using Nikon DTM 322 Total Station. Height estimation of the network
points was done using least squares adjustment methods using observation model
with minimum constraint. Pope�s Tau data snooping was performed with 95 % level
of confidence to evaluate the result. Network quality analysis was then undertaken by
evaluating the precision of the estimated height and the correlation number between
estimated parameters was used to analyze the strength of figure. Furthermore, point
displacement analysis was performed using student-t statistical test with 95% level of
confidence.
The results showed that the average precision of the leveling network in 2011
was 0.003 while the trigonometric leveling in 2012 was 0.029. Based on the height
closure error value, the leveling network met the the LAA class while the
trigonometric leveling met the LA class. Strenght of figure analysis indicated that in
general the correlation value between estimated parameters in leveling network was
bigger than Total Station network. Furthermore, the height differences between 2011
and 2012 showed the displacement between -0.010 to -0.099 m, but the statistical test
indicated that these displacements were insignificant. It can be concluded that the
trigonometric leveling network using Total Station in this study has not meet the
required precision for Borobudur deformation study.
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