EXPERIMENTAL RESEARCH ON DEVELOPMENT OF THE ANALYTICAL EARTH’S TERRAIN MODELS
Analytical terrain models use functional dependencies to describe earth’s surface elevations. This kind of models may be used in various fields of study e.g. geomorphology, gravimetry, cartography. The main purpose of this article is to assess the applicability of analytical models to describe landforms of diverse complexity - mountains, hills and plain. Due to complexity of earth’s terrain it is possible to describe it only via using approximation methods. In this article one of the linear integral expressions methods (S-approximation) was chosen as approximation algorithm. The main S-approximation model parameters are number of approximation planes and their depth. For the research three experimental areas on the territory of Spain were used. The unique model parameters for each experimental area were calculated. Results of statistical and visual accuracy assessment of elevations reconstructed by developed analytical models show that S-approximation method to an adequate degree describes each experimental area. Approximation accuracy depends on vertical and horizontal ruggedness of modeling terrain. The main differences between source and approximated terrain are located on structural landforms (ridges and thalwegs). It is possible to improve accuracy by increasing the number of input data and tuning model parameters. It was also revealed that analytical terrain models could be used for detection of anthropogenic objects and vegetation on elevation models.