## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Number of** & **Line** & & \multicolumn{2}{c}{**Number**} & \multicolumn{3}{c}{**Mean Length [km]**} & \multicolumn{3}{c}{**Mean Error After Adjustment**} \\
**Campaign** & **Length** & \multicolumn{2}{c}{_Traverses_} & \multicolumn{2}{c}{_Lines \(n_{L}\)} & \multicolumn{2}{c}{_Sections_} & \multicolumn{2}{c}{_Traverse_} & \multirow{2}{*}{_Line L_} & \multirow{2}{*}{_Sections_} & \multirow{2}{*}{**[mm]**} \\
**\#1** & & & & & & & & & \\
**(1926–1937)** & **10,046** & **36** & **121** & **5907** & **445** & **83** & **1.7** & \(\pm\)1.04 \\ \hline \#2** & & & & & & & & & \\
**(1953–1955)** & **5778** & **12** & **60** & about 4500 & **609** & **96** & **1.3** & \(\pm\)0.78 \\ \hline \#3** & & & & & & & & & \\
**(1974–1982)** & **17,015** & **135** & **371** & **15,827** & **221** & **46** & **1.1** & \(\pm\)0.84 \\ \hline \#4** & & & & & & & & & \\
**(1997–2003)** & **17,516** & **138** & **382** & **16,150** & **217** & **45.8** & **1.085** & \(\pm\)0.88 \\ \hline \end{tabular}
\end{table} 
Table 3: Documented results from 4 leveling campaigns in Poland from 1926 to 2003 (source: own study). Failure to close the loops in double-leveling nets #3 and #4 exceeded the limits in two loops. The total number of loops was 128, and the average \"not fully closed\" error was \(+-\) 0.15 mm/year. The model (VCM2006) is related to the tide gauge in Wladyslawowo, where the average velocity of change in the level of the Baltic Sea was determined based on tide gauge data. A total of 366 common leveling lines were defined and 222 common nodal points (Figure 1) were used in this research. The vertical movements between benchmarks are shown in Figure 2. Errors in the determination of vertical displacements on the 1 km double-leveling line were 99% less than 0.1 mm/yr. Permanent GNSS stations do not form a network structure similar to a leveling network. The development of relative vertical movements of the Earth's crust from GNSS data based on the simultaneous adjustment method requires the determination of vertical movements between permanent GNSS stations. This designation can be carried out in two ways: The first, presented in [6; 10], involves selecting one GNSS station as the main one and calculating the vertical movement between this station and neighboring stations; in a slightly modified form, vertical movements are counted between all stations used. Figure 1: Simplified double-leveling net #3 and #4 (vertical movement network)—on the (**left**); model of vertical crustal movement from 2006—on the (**right**) (source: [37]). Figure 2: Vertical movements on leveling lines (source: own study). A different approach was used in [27], where the vertical movements between stations were determined based on the difference in the time series of coordinates of neighboring stations. Connections between stations were based on Delaunay triangulation [14]. Delaunay triangulation is the triangulation of a set of points P in the plane, such that no point from the set P is inside the circle described on the triangle belonging to the triangulation. Vertical movements at permanent GNSS stations are determined as a linear trend based on coordinate time series, which are subject to decomposition [38]. At this stage, outliers, spikes, seasonal components, signal noise, the influence of tide models, etc., are removed [39]. There are many computational strategies for each decomposed factor [40; 41; 42; 43; 44; 45; 46; 47]. Station coordinates can come from double-difference solutions [10] or Precise Point Positioning (PPP) solution [48; 49]. In Poland, the vertical movement was determined at all permanent stations of the ASG-EUPOS network from 2011 to 2021 (11 years) based on the PPP solution [5]. This is the latest study of this type in this area (Figure 3). Its advantage is the use of long coordinate time series data [50]. The largest movements were observed in the mining area (southern Poland) located on the Western European plate.