## 3 Results
### Analysis of Coordinate Differences  
To evaluate the detailed differences among the estimated horizontal coordinates, we performed a comparative analysis of the residuals between the GAMIT/GLOBK and Bernese solutions with respect to the official KGD2002 positions. These residuals--expressed in the local topocentric North-East-Up (NEU) system--reveal subtle but meaningful patterns that help assess the internal consistency and potential biases of each processing approach. This section aims to provide a comprehensive visual and statistical exploration of these differences using multiple complementary representations:  
1. Two-dimensional density maps to show the spatial distribution of the residuals;
2. Scatter plots to illustrate the spread and concentration of points;
3. Polar histograms to examine directional tendencies in the horizontal residual vectors. Each method serves a specific interpretive purpose. Density maps highlight where most of the coordinate differences are concentrated, offering insight into central tendencies and outlier structures. Scatter plots help reveal the dispersion and clustering behavior, while polar histograms provide information on azimuthal directionality that may be related to network geometry, presenting strategy, or localized effects. We applied these visualizations consistently to three key comparison groups:  
* GAMIT/GLOBK vs. KGD2002;
* Bernese vs. KGD2002;
* GAMIT/GLOBK vs. Bernese. The goal is not only to assess how each solution agrees with the national reference frame but also to compare the internal coherence between the two software outcomes. By representing residuals in the \(\Delta\)E-\(\Delta\)N plane and examining directional patterns, we gain a multi-perspective view of the solution space that complements basic RMS statistics. These results are illustrated in Figure 10, which displays side-by-side comparisons for each group across the three visualization modalities. Figure 10 presents a side-by-side visual comparison of horizontal residuals among the three coordinate solutions. Each column corresponds to a solution pair and includes a 2D density map, a scatter plot, and a polar histogram of azimuthal directions in the \(\Delta\)E-\(\Delta\)N plane. In all three cases, the residual distributions are generally centered around the origin, suggesting no large systematic offset in either the east or north direction. However, distinct patterns are visible across the three comparison groups. In the GAMIT vs. KGD2002 column (left), the density map and scatter plot indicate a compact, symmetric distribution, with most residuals falling within \(\pm\)10 mm. The polar histogram shows a fairly uniform spread, indicating that the directions of horizontal residuals are azimuthally random and not significantly biased toward any specific direction. The Bernese vs. KGD2002 residuals (middle column) appear slightly more dispersed than those from the GAMIT comparison. While still centrally concentrated, the scatter plot shows a broader cloud, and the polar histogram reveals a mild directional preference toward the southwest (around 240-270\({}^{\circ}\)). This suggests the possibility of small systematic effects or station-dependent factors in the Bernese adjustment relative to the national datum. The GAMIT vs. Bernese comparison (right column) exhibits the widest spread among the three, with residuals extending beyond \(\pm\)20 mm in several cases. The density peak remains near the origin, implying general agreement, but the scatter plot is noticeably more dispersed. The polar histogram remains relatively flat but shows a slight clustering in the east-west directions, possibly reflecting subtle differences in the network geometry handling or baseline weighting strategies between the two software packages. Taken together, these visualizations indicate that both GAMIT and Bernese solutions are closely aligned with the KGD2002 reference, with GAMIT showing slightly tighter agreement.