The use of GIS technologies for the analysis of geodetic provision of the territory of the Dnistrovsky district of the Chernivtsi region

Abstract

The existing geodetic provision of most of the territory of our country requires an increase in the number of points of the state geodetic network. In today's conditions, the analysis of the geodetic provision of the territory is extremely important and relevant. The latter is even more strengthened due to the implemented decentralization reform, which changed the administrative-territorial structure of the country. That is why it is necessary to carry out analysis, calculations, determine the features of spatial placement and distribution of both individual points of the DGM and geodetic support in general. The purpose of the study is the analysis of geodetic support using QGIS GIS of the territory of the Dnistrovsky district of the Chernivtsi region in conditions of decentralization. Methodology: GIS analysis methods were used to solve the problems that were formed in the work. Thanks to the software product QGIS, thematic layers were vectorized and based on them, maps were created, which allow to evaluate the existing geodetic support in the section of the newly created administrative and territorial units of the study area. Cartographic, statistical-mathematical, descriptive methods made it possible to determine the number and area of areas of territories that are characterized by inconsistency of geodetic support with regard to the requirements for the placement of DGM points for creating maps of the appropriate scale. Today, the geoportal of the State Government of Ukraine, the official website of decentralization is temporarily closed. Therefore, the use of GIS technologies in combination with topographic maps allows a slightly different approach to the analysis and assessment of the geodetic provision of the territory. The existence of separate, separate databases both at the state and regional levels makes it even more impossible to conduct an objective assessment. In view of the above, there is a need to analyze the topographic and geodetic support of the territory of Ukraine using GIS technologies. Research result: The number of geodetic points is 70 units, which is 26,4 % of the total number of points in the region (1st class – 7 units; 2nd class – 13 units; 3rd class – 29 units; digit geodetic network – 21 units). Vectorization of the objects characterizing the areas of inconsistency in the average density of DGM points was carried out. The total area is 600,6 km2 (28,3 % of the total area of the district). Thanks to QGIS, map sheets with a scale of 1 : 200 000 of the geodetic support of the territory as of the 60-s of the 20-th century were linked. The number of DGM points is 73 units. Moreover, 57 points have the same spatial arrangement in comparison with modern points. The correspondence of the geodetic support was considered and it was established that the area of the territory with indicators of non-compliance is 603 km2, which corresponds to 28.4% of the total area of the district. An assessment of the geodetic support of the territory was carried out, taking into account modern and lost points of land surveying. The area of non-conformity areas decreases from 600–603 km2 to 419,8 km2, which, as a percentage of the total area of the Dnistrovsky district, is a decrease from almost a third of the territory to its fifth part – 19,8 %. Scientific novelty: separate thematic vectorized polygonal layers of the territories of the settlements of the districts and modern territorial communities of the Dnistrovsky district of the Chernivtsi region were created, which made it possible, thanks to GIS technologies, to quantitatively determine the area of the territories, with the inconsistency of the geodetic support regarding the requirements for the placement of DGM points when creating cartographic materials of the appropriate scale. In this way, the inconsistency of the geodetic support of the territory of the Dnistrovskyi district with regard to the requirements of regulatory documents was established. Vectorization of areas of discrepancy in the average density of DGM points made it possible to quantitatively approach the assessment of geodetic support in terms of territorial communities. Solving the specified problem is possible thanks to the design and creation of additional points of DGM. The use of geodetic points that existed in the past years and their location can improve the geodetic support of the research area. Keywords: geodetic support, GIS, decentralization.