Evaluation of nodes distribution for linear terrain objects to calculate the optimal parameters of coordinate reference systems in terms of the Republic of Chile

Abstract

The article focuses on the need to evaluate the distribution of coordinates of the object nodes and their filtering (discharge) in order to implement algorithms for calculating the optimal parameters of projection coordinate systems. To solve this task, it is proposed to use the uniform distribution function, the value of which characterizes the concentration degree of the nodes that form the contour of linear objects. At the same time, the Chi-square criterion, as an estimation indicator, allows implementing iterative procedures for combining nodes and generalizing parts of objects to approximate the initial data to the uniform distribution. Studies have shown that it leads to the reduction in the excess concentration of nodes of linear terrain objects, which negatively affects the calculation of optimal parameters for coordinate reference systems. The paper also considers the examples of coordinate systems parameters, which are, moreover, implemented on the basis of oblique map projections, the use of which is possible for solving a wide range of engineering tasks for transport facilities, agriculture and environment studies of the Republic of Chile. The article also provides a graphical comparison of the suggested single 6-degree zone for the specified class of projections with the SIRGAS-Chile coordinate system using the Universal Transverse Mercator coordinate system (UTM Zone 18 and Zone 19). In conclusion the author presents the data that prove the necessity for the mandatory evaluation of the uniformity of initial geodata distribution in order to find the best projection parameters.