## 3 Results
To give an idea of the degree of accuracy of the mosaic alignment (especially in relation to the data layer on the Mapire.eu website), a new control layer of more than 50 GCPs was created, which were approximately evenly distributed over the area of Bohemia. When designing these points, those that had already served as GCPs of the main IRLS adjustment method or points in their vicinity were excluded in order to avoid influencing the results of the comparison. The GCPs used for Mapire.eu are not known, however, given the small number of them, it can be assumed that the probability of using one of them in the control comparison is very low. All types of usable objects were chosen as points in equal numbers (with the exception of churches, which practically had been completely used in the main adjustment before) and, in addition to the current maps, the maps of the Second Military Survey were also used to identify the objects. The coordinate differences between the ideal position and the position within the adjusted map layer were tested. From the results it is not possible to unambiguously decide which dataset is better adjusted. Fifty GCPs are not able to convincingly cover the territory of Bohemia and it is especially the Mapire.eu data--which seem to show relatively large local deformations--that would need more GCPs for quality assessment. The median of the position deviation is around 250 m in both cases. The mean value is slightly weaker to the detriment of Mapire.eu, but the difference is negligible. Additionally, while Mapire.eu shows a larger amount of minor deviations, the mosaic using IRLS does not show errors greater than 1300 m, which value is exceeded by Mapire.eu in four cases, and the deviations end beyond the value of 2 km here. We visualized the resulting mosaic in the ArcGIS Pro environment as a mosaic dataset. This data type allows storing raster data along with their footprints, which define the mask of the image in the mosaic. The footprints are also the output of our software, which automatically generates shapefiles from transformed map sheet corner coordinates, \begin{table}
\begin{tabular}{c c} \hline
**GCP Category** & **Weight** \\ \hline church & 1 \\ château, yard, farmstead, monastery & 1.4 \\ mill & 2 \\ path crossing & more than 3 \\ \hline \end{tabular}
\end{table} 
Table 2: Weight estimates of particular GCP categories. Figure 6: Examples of different types of GCPs collected (church, yard, path crossing). creating a new map sheet definition. These generated shapefiles are then paired with the footprints and used to crop the out-of-frame image of individual map sheets. When adjusted map frames are available for individual map sheets, it is possible to create a seamless map layer using a mosaic dataset (we used the mosaic dataset of the ArcGIS software, ESRI platform) similar to that available on the mapire.eu website. The Mosaic Dataset allows a number of settings for the resulting visual display, rendering order, color corrections, rendering speed, etc. Using ESRI tools, it is possible to publish a raster mosaic as a web map service, both OGC-typed and proprietary. The Image service, which is available in the ArcGIS Server extension named Image Server, was used to publish the First Military Survey mosaic. This type of service provides fast tiled data, and, at the same time, this map layer can be published as OGC standard WMTS.