V članku analiziramo metodo izgradnje digitalnega modela reliefa iz podatkov lidar na testnih primerih z območja Slovenije. Ker obe metodi temeljita na konceptih matematične morfologije, podrobneje ...predstavimo eno, medtem ko uvodoma podamo splošen pregled del na obravnavanem območju. Rezultati pokažejo, da se z obema metodama pravilno določi teren v več kot 90 odstotkih, in sta zato obe primerni za uporabo tudi na geografsko tako razgibanem območju, kot je Slovenija. Čeprav je na ravninskih območjih njuna natančnost primerljiva, opisana metoda omogoča natančnejšo izgradnjo digitalnega modela reliefa predvsem na zahtevnejših, goratih območjih z relativno strmimi in spremenljivimi nakloni ter na območjih s terasami. Tudi v teh primerih povprečna absolutna višinska napaka ni večja od 15 centimetrov ; This paper reviews two methods for digital terrain model generation from LiDAR data in test cases in Slovenia; both methods are based on concepts of mathematical morphology. A general overview of methods is given in the introduction, one of which is presented in more detail. The results show that both methods are able to correctly extract terrain points in more than 90% of the cases and are, therefore, suitable for usage even for such geographically diverse regions as Slovenia. Although the accuracy of both methods is comparable in cases of flat areas, the described method performs significantly better in problematic cases, such as hilly areas with relatively steep variable slopes, and terrains containing terraces. Even in these cases, the average absolute height error is not higher than 15 cm.
Mathematical modelling is a common approach when assessing debris-flow hazards. In this study on the mathematical modelling of debris flows, we applied the widely used Flo2D model. The high accuracy ...of the input parameters is essential for obtaining acceptable results. The numerimi grid in the area of the debrisflow movement is generated from topographic data. The aim of our research was to assess the usefulness of public data for debrisflow-modelling and to compare this data to the LiDAR-derived data. In Slovenia, DEM 5 and DEM 12.5 are publicly available data. However, the morphological accuracy of these dataseis is questionable because of their development methods and their low morphologic resolution. A better solution is LiDAR-derived data with higher resolutions and a multiple options for further improvements with different methods and algorithms. The results with LiDAR data are more accurate-, the torrential channel is better expressed. One downside of LiDAR data is its high price, which prevents wider usage of more precise data. Another downside is the much longer computational times of the model. More precise data means a more agitated surface of the computational grid, which results in shorter computational steps to ensure numerical stability. Methods for LiDAR-derived DEMs improvements are proposed in this study. With modified data, computational times are much shorter and results are even more precise than with non-modified DEMs.
In the introductory chapter, the author explains the term “digital elevation model”~outlines the features of the 100-meter digital elevation model of Slovenia~presents relief as a component part of ...the landscape, the geographic information system, and maps~derives a special coefficient for surface undulation based on changes in altitude and inclination~describes the method for determining relationships between relief and other components of the landscape~and outlines the basic characteristics of the surface of Slovenia.The central chapters are devoted to presenting the characteristics of altitude, inclination, and surface exposition determined by the author using the 100-meter digital elevation model. On the basis of an analysis of numerous relief elements, primarily altitude, inclination, and relief coefficients, the author defines the relief units of Slovenia and calculates the relationship between relief and several other landscape elements, in particular rocks, vegetation, population, and settlement patterns.
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