# The Influence of the Quality of Digital Elevation Data on the Modelling of Terrain Vehicle Movement
## 5 Conclusions  
This research studied the possibilities for raster analyses of elevation models and other options for their evaluation and effective usage. One of the most important results of this study was the introduction of the method of slope reduction for low-detail elevation models. Furthermore, the goal was to determine the strengths and weaknesses of selected data for use in cross-country mobility analyses, supplemented by recommendations on how to use these databases efficiently. The selection of databases was determined by the focus of data development projects of NATO and current scientific research projects of the Ministry of Defence of the Czech Republic. The presented methodology of data assessment for the purposes of military geographical analysis of the terrain can be further used in military practice, e.g., in foreign missions where high-detail data may not be present. Key findings of the elevation models analysis show the potential of their usage in practise. DTM 5, which is a model with a minimum resolution of a grid of points of 1 m \(\times\) 1 m, is the most detailed model in terms of the evaluation of slopes and passability. It can be replaced by using DTM 4 (5 m \(\times\) 5 m) in terrain analyses, for example, the slope reduction for 30\({}^{\circ}\) slopes is 2.2\({}^{\circ}\). The elevation model with lower detail DTM 3 (10 m \(\times\) 10 m) had a 4.9\({}^{\circ}\) slope reduction for 30\({}^{\circ}\) slopes and DTED 2 (30 m \(\times\) 30 m) had a 6.4\({}^{\circ}\) reduction. These models can be used for general analyses of less fragmented terrain.  
The selected areas, where analyses were performed, were a balanced sample of the landscape. It allowed for the assessment of the most important terrain parameters that have a fundamental influence on the conduct of military operations. Nevertheless, it is necessary to perform a complete validation of the slope reduction method from other various representative regions across NATO AOR (territory of NATO nations) and NATO AOI (territory beyond NATO nations). A larger number of locations would enable a more accurate determination of the reliability of databases when used in the cross-country mobility analysis. The challenge NATO has is a limited global short-notice availability of detailed digital terrain models. Without these models, no detailed and accurate CCM analysis can be performed. The only option is to process available elevation models into a form that allows for acceptable results, such as the slope reduction method.  
Conceptualisation and methodology, J.R. and M.R.; model programming, J.R.; validation, J.R. and M.R.; writing the paper, J.R. and M.R.; original draft preparation, M.R. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The study data were provided by the Military Geographic and Hydrometeorologic Office, Dobruska.  
This paper is a particular result of the defence research project DZRO VAROPS managed by the University of Defence in Brno, NATO--STO Support Project (CZE-AVT-2019) and specific research project 2021-23 at the department K-210 managed by the University of Defence, Brno.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.