# A Blockchain Copyright Protection Model Based on Vector Map Unique Identification
## 5 Experiment Results and Analysis
### Experiment
#### 5.3.4 Robustness Experiment
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Watermarked Vector Map**} & \multirow{2}{*}{**Data Accuracy**} & \multicolumn{3}{c}{**Error Index**} \\ \cline{3-5}  & & **Maximum Distance** & **Mean Distance** & **Standard Deviation** \\ \hline Shanghai dataset & 0.1 m & 3.20 \(\times\) 10\({}^{-4}\) m & 1.61 \(\times\) 10\({}^{-5}\) m & 6.54 \(\times\) 10\({}^{-6}\) m \\ Beijing dataset & 0.1 m & 4.00 \(\times\) 10\({}^{-4}\) m & 2.94 \(\times\) 10\({}^{-5}\) m & 2.28 \(\times\) 10\({}^{-5}\) m \\ Chengdu dataset & 0.1 m & 3.70 \(\times\) 10\({}^{-4}\) m & 2.03 \(\times\) 10\({}^{-5}\) m & 1.42 \(\times\) 10\({}^{-5}\) m \\ Jiangsu dataset & 0.1 m & 2.75 \(\times\) 10\({}^{-4}\) m & 1.35 \(\times\) 10\({}^{-5}\) m & 5.80 \(\times\) 10\({}^{-6}\) m \\ Hangzhou dataset & 0.1 m & 2.85 \(\times\) 10\({}^{-4}\) m & 1.69 \(\times\) 10\({}^{-5}\) m & 7.34 \(\times\) 10\({}^{-6}\) m \\ Nanjing dataset & 0.1 m & 4.02 \(\times\) 10\({}^{-4}\) m & 2.67 \(\times\) 10\({}^{-5}\) m & 2.02 \(\times\) 10\({}^{-5}\) m \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Error statistics of data. ters, which are designed to handle the global relationships between layers, mitigating the impact of layer-level changes. Cropping and merging operations are frequently performed in GIS when focusing on specific regions or integrating datasets [48]. Experiments incrementally applied these operations at 10% intervals, ranging from 10% to 50%. The results, shown in Figure 11h,i and Table 5, indicate that although BER increased with higher cropping and merging ratios, the BCPM-UI and [PERSON]'s models exhibited the slowest growth. This robustness is due to the model's reliance on geometric and topological invariants, which remain stable under partial data modifications. Format conversion is a practical consideration for GIS platforms, where data interoperability often requires conversion between formats. Watermarked maps were converted into DWG, E00, and GDB formats and reverted to Shapefile format for extraction. Table 6 summarizes the results, showing that unique identifiers and watermark information were successfully retrieved in all cases. The NC values consistently remained at 1, and BER values stood at 0, demonstrating robustness across diverse formats. Reordering attacks simulate scenarios where the storage order of geographic features is altered [49], a frequent occurrence during data processing or transmission. The BCPM-UI model embeds watermarks and constructs unique identifiers based on index positions and values, rendering it immune to such alterations. The experimental results confirmed that \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Data Format**} & \multicolumn{3}{c}{**NC**} & \multicolumn{3}{c}{**BER**} \\ \cline{2-7}  & **Chengdu** & **Nanjing** & **Shanghai** & **Chengdu** & **Nanjing** & **Shanghai** \\  & **Dataset** & **Dataset** & **Dataset** & **Dataset** & **Dataset** & **Dataset** \\ \hline dwg & 1.00 & 1.00 & 1.00 & 0.00 & 0.00 & 0.00 \\ e00 & 1.00 & 1.00 & 1.00 & 0.00 & 0.00 & 0.00 \\ gdb & 1.00 & 1.00 & 1.00 & 0.00 & 0.00 & 0.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The robustness results of format conversion attacks. Figure 11: Robustness experiment results: (**a**) rotation attack; (**b**) scaling attack; (**c**) translation attack; (**d**) object-add attack; (**e**) object-delete attack; (**f**) layer-add attack; (**g**) layer-delete attack; (**h**) cropping attack; (**i**) merge attack. reordering geographic features had no impact on the constructed identifiers or watermarks, with NC values consistently at 1. The rationale behind selecting these specific tampering scenarios lies in their prevalence and relevance to real-world GIS applications. Geometric transformations, object and layer modifications, cropping, merging, format conversions, and reordering represent common operations and potential attack vectors in GIS workflows.