The fourth precise levelling campaign of Poland in 1999-2003
Lyszkowicz, Adam & Marcin Leonczyk
The re-levelling of the 1st order vertical control network in Poland with total length of 382 lines of 17 516 km had started in May 1999 and was completed in June 2002. First, the paper describes, equipment used in the field measurements, method of levelling, corrections introduced to raw observations. Then in order to estimate the levelling accuracy, the observed height differences were both statistically and classically (Lallemandds and Vignalls formulas) analyzed to see distribution of systematic and random errors in the network. Accuracy of the levelling network computed from Lallemandds formulas is 0.27 km / mm for random mean error and 0.08 mm/km for systematic mean error. According to Vignalls formulas, random mean error is 0.27 km / mm and systematic mean error is and 0.44 mm/km. To better understand the character of systematic errors, the levelling observations were studied by the variance and covariance methods, which showed that the lines are affected by systematic errors.
Event: 5th FIG Regional Conference for Africa : Promoting Land Administration and Good Governance
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