## 2 Materials and Methods
### Digital Relief Model Specification  
The Geodesy, Cartography, and Cadastre Authority of the Slovak Republic currently provides the digital relief model 3.5 (DMR 3.5). Unlike the DTM, which represents the course of the terrain, without objects on it, and works with all types of GeoElements such as points, lines, and polygons, the DMR is a digital representation of terrain relief, composed of data and an interpolation algorithm which allows altitudes to be derived at arbitrary points located within the modeled area. DMR 3.5 was developed from DMR 3, which was created by vectorizing topographic maps with a scale of 1:10,000 and in some small areas from maps with a scale of 1:25,000. Subsequently, a grid with technical parameters of \(10\times 10\) m was generated. As it turned out later, DMR 3 showed significant errors in some places, mainly in flat areas, some valleys and basins, but above all, it was not harmonized  
Figure 6: Histogram (with Normal Curve) of m\({}_{\text{3D}}\) [mm]. Figure 7: Anderson—Darling Normality Test of m\({}_{\text{3D}}\). with the shape of watercourses and water areas. DMR 3.5 is based on the original DMR 3.0 model, where various types of adjustments were made, such as correction of gross errors, remodeling of areas from photogrammetrically evaluated data, or their replacement with DMR 4.0 data in selected locations. DMR 4.0 started being created by means of the photogrammetric method in 2004, but due to time-consuming and slow workflow, this task was stopped in early 2009. Various tests have shown that the differences from actual values are up to 15 m in rugged high-altitude areas, such as some parts of the High Tatras [57]. A qualitative enhancement of flood modeling will be provided by the digital relief model DVRM 5.0 (Airborne laser scanning and DMR 5.0 [[https://www.geoportal.sk/sk/udaje/lls-dmr/](https://www.geoportal.sk/sk/udaje/lls-dmr/)]([https://www.geoportal.sk/sk/udaje/lls-dmr/](https://www.geoportal.sk/sk/udaje/lls-dmr/))), based on aerial laser scanning with the required density of at least five last reflection points per square meter. The required absolute accuracy of point cloud height must not exceed the mean height error of 0.15 m, and the required DMR 5.0 height accuracy in the ellipsoidal coordinate system ETRS89 must not exceed the mean height error of 0.20 m [58]. The completion of the DMR 5.0 project is scheduled for 2022. The process of decision-making and planning in river basin management is based on the qualitative aspect of the digital relief model. The qualitative aspect of DMR creation is specified by the degree of purpose for which the DMR is processed. The practical assessment of the DMR quality on the selected segment reach of the river Torysa, flowing through a residential area of the city of Presov, relied on theoretical recommendations for quality assessment provided for the given type of file source with spatial information. The qualitative aspect is directly connected to the actual level of processing. The propagation of random errors and errors caused by human factor represents the first stage of assessment. This regards inaccuracies stemming from the method of obtaining spatial data selected for the creation of the DMR. The second category of inaccuracies arises from the method of representation and subsequent approximation of details (especially density of points and grid cell size). The third level of inaccuracies, which lowers the output quality of the DMR, is the method of choice (selection) of mathematical algorithms for final processing of the expected result. Applying the recommended theoretical basis of data quality assessment, as specified in the theoretical concept and background (Figure 1), it was possible to present the following facts related to the final quality of the DMR in the process of hydrodynamic modeling, up to a detailed level. DMR quality assessment for the needs of hydrodynamic modeling is based on the following:  
1.