Skaitmeninio reljefo modeliavimo daugiaparametrinis vertinimas, atsižvelgiant į paviršiaus geomorfologines savybes

Topicality of the research. In compiling digital terrain models (DTM) as well as in evaluating them there are widely applied mathematical statistical measuring data processing and analysis methods. However in compiling digital models of relief and evaluating them there are certain peculiarities in mathematical statistical data application. These peculiarities are caused by the fact that relief modeling as well as analysis is considered to belong to the group of geostatic problems. The latter are peculiar for the initial results of measuring which are medium between purely random and purely determined sizes. In solving geo-statistical problems, one has to make use of regionalized data, the stochastic characteristics are the functions of geographic positions of the territory. In modeling the relief the surface geomorphologic peculiarities determine the characteristics of the functions of geographical position. Theoretical grounding of the methods used in modeling the relief surface (e.g., kriging, spline, invert distance weight (IDW), polynomal) is based on the statistical analysis of the random values. Due to the fact that the characteristics of geo-statistical measuring data are preconditioned by the geographic position, not in all territories there are equally suitable certain methods of modeling and parameters of modeling algorithms. The mentioned above reasons determine the fact that there do not exist unified digital terrain modeling methods and types, to be equally well applied for all the territories. Caused by the great variety of characteristics of the land surface relief it is possible to compile a qualitative model of the relief only if separate modeling methods have to be applied as well as parameters of modeling, after having evaluated regional geo-statistic data peculiarities. It is necessary to compile a unified technique for relief classification by selecting the best applicable relief modeling method and using it as the base to carry out detailed investigation. Objective of the research. To investigate the accuracy dependence of digital terrain models on the methods of initial data preparation, methods of modeling, parameters of modeling, relief geomorphic characteristics as well as to determine the priorities of availability of modeling methods for different forms of the relief. The following goals have been set to develop an effective model: •To investigate accuracy dependence of the digital terrain model on the methods of initial data preparation. •To work out a system of evaluation and classification of land relief geomorphic characteristics and carry out the zoning of the territory. •Examine the influence of parametric functions of modeling methods to the accuracy of the model. •Explore the influence of modeling parameters to different relief types. •To investigate the influence of modeling methods to the accuracy of the relief model. •Compile regressive models based on the experimental results, summarizing the correlations between the accuracy of the relief models, modeling parameters and geomorphic characteristics of the relief. •Evaluate the quality and priority of digital terrain models by means of multi criteria analysis. Research object. The digital terrain models of the territory of Lithuania and the measured initial data by means of different techniques in order to compile them. Methods of research. Experimental quality investigations of digital terrain models by means of technologies of geographic systems, the mathematical statistical and multi criteria analysis of the results of investigations. Scientific novelty of the research work: •It has been determined dependence of the accuracy of digital terrain models from the methods of parameters of modeling, and geomorphic characteristics of the relief. •There have been compiled regressive models describing the dependence of the accuracy of the relief models received by using different models on the parameters of modeling and geomorphic indexes of the relief. •There has been applied for the first time the multi criteria analysis in evaluating the quality and priorities of digital terrain models. Practical value of the research work: Based on the received results of the research and splitting into zones the geomorphic relief it has become possible to select the most suitable methods of modeling and parameters of modeling with different characteristics for the territory and compile better quality of relief model for the whole territory. The statements to be defended: •Classification of the relief according to the geomorphic characteristics. •Regularities of the influence of modeling methods and their parametric functions as well as parameters of modeling to the quality of digital relief models, subjected to the characteristics of geomorphic relief. •Possibilities of application of multi criteria analysis in evaluating the quality of digital terrain models and priorities of modeling methods. Approval of the research work. The results of the carried out research have been published in 5 publications in the periodical scientific journals of Lithuania and in publications of the material of 4 conferences. The presentations have been made in 2 international and 4 scientific conferences in the country.