## 5 Discussion and Conclusions  
In the metric documentation of cultural heritage, we often come across two terms--accuracy and resolution. While resolution refers to the detail of the documentation, accuracy refers to the possible errors that the measurement may contain. When documenting architectural objects, the standard drawing scales for facades, floor plans, and vertical sections are 1:50 or 1:100. These correspond to a 5-10 mm resolution: for example, 10 mm in reality will be displayed as 0.1 mm in 1:100 scale, which is the physical limit for drawing details in analog form. However, for a combination of an architectural object and archaeological finds, it is necessary to increase the detail (and scale) of the documentation, e.g., due to the visibility of stone mason marks in the texture. An archaeologist does not need to be interested in whether a given stone marker is placed in relation to the whole object with an accuracy of 1 mm or 10 mm; the important thing is that it is visible. Therefore, the overall accuracy of the documented object could meet an accuracy of 10 mm, but with a resolution of 1 mm. However, the size of the permissible deviations should also depend on the size of the object, and therefore it is appropriate to express the achieved accuracy as the ratio between the deviation and the size of the object, which is the purpose of relative accuracy. Digital photogrammetry makes it possible to achieve a high relative accuracy, in the range of 1:20,000 [30], 1:100,000 [31,32], or, in exceptional cases, of up to 1:1,000,000 [33]. However, without sub-pixel measurement of coded targets, such accuracy cannot be achieved and is not even necessary for most heritage applications, except for deformation monitoring. Of course, the accuracy of photogrammetric measurement depends not only on the configuration of the camera network or the use of control points, but also on the combination of camera, lens, photogrammetric software, and processing settings. Since digital SLR cameras are still widely used for photogrammetric purposes and most users of SfM photogrammetry software use the standard recommended settings, in this case study, we decided to emphasize the influence of different camera networks on the deformations of the 3D model of the architectural object and not to test different combinations of photographic equipment and processing settings. When testing various configurations of the camera network within the Saint James Chapel documentation, in some cases, we found deviations at a level of more than 8 mm, \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Comparison**} & **Standard Deviation** & **Points with Dev. \textless{}10** & **Points with Dev. \textless{}5** \\  & **(mm)** & **mm (\%)** & **mm (\%)** \\ \hline
**TLS vs. A after ICP** & 7.0 & 95.5 & 85.6 \\
**A vs. B** & 8.0 & 94.4 & 82.1 \\
**A vs. C** & 7.8 & 93.6 & 90.3 \\
**A vs. D** & 8.2 & 93.6 & 78.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Statistics from the comparison of all variants. especially in the case where only one opening was used to connect the exterior and interior (variant B). The exposed part of the chapel has the largest dimension of 12 m--a total deviation of 8 mm then corresponds to a relative accuracy of 1:1500. However, the ossuary in the basement is only 7 m long, and within it, in some cases (variants B and D), deviations of up to 10 mm were achieved (e.g., Figure 18), which corresponds to a relative accuracy of 1:700 compared to the size of the ossuary, i.e., twice as bad as for the entire chapel. In particular, deviations in the height setting of the ossuary could lead, for example, to incorrect determination of the ceiling thickness or incorrect interpretation of deformations and displacements caused by the environment in the case of long-term monitoring. TLS and photogrammetry are mainly used for cultural heritage objects because of the non-contact nature of these technologies.