1.1.1 Traditional geodetic methods for studying landslide
processes
The use of traditional theodolite and total station measurements can
achieve millimeter-scale errors when determining point coordinates
(Savvaidis, 2003). Generally, a relative coordinate system is used for
the survey which creates a problem when comparing such data with
geo-referenced data sources. It is therefore necessary to recalculate
the position of the field points to allow plotting these into the global
coordinate system by specific position of the reference points (Gupta &
Shukla, 2018).
The advantage of this surveying method is its high accuracy. The
disadvantage is that the surveys take a long time; therefore, a limited
number of points located in accessible places are selected. The
development of TLS, UAVs, allowing to take large amounts of data in a
short time, precisely and in detail describing the surveyed surface,
makes the classical topographic survey an outdated approach (Barbarella
& Fiani, 2013).
A limited control of processes operating within the landslides and the
displaced ground masses are the most significant disadvantages of
traditional approaches. None of these methods provides comprehensive
information on quantitative characteristics and mechanism of erosion
processes on slopes. Thus, the most effective methods for studying
inaccessible slopes with landslides are the repeated morphological
surveys with accurate referencing of multi-temporal data.