Updating of digital topographic maps in the new national spatial coordinate system: case Fergana valley in Uzbekistan

Dilbarkhon Fazilova,Hasan Magdiev

doi:10.5194/ica-proc-4-31-2021

Abstract

Abstract. The classical geodetic coordinate system (CS42) in Uzbekistan uses the Krasovsky ellipsoid. The implementation of new information technologies, such as the Global Navigation Satellite System, became the basis for the development of a new national open geocentric coordinate system. This paper describes the development of a distortion grid for transforming horizontal spatial data from the local geodetic datum CS42 to a geocentric datum WGS84 for 1:100000 scale maps of the Fergana Valley in Uzbekistan. A first version of the distortion grid file has been created for transforming between CS42 and WGS84 for the whole territory of the country. The significant influence of the longitudinal drift of the region has been confirmed. The grid was used to transform topographic maps at a scale of 1:100000 for the Fergana Valley. Changing the map datum has shifted the grid of coordinate systems by 70 m in the East and 7 m in the North.

Highlights

The implementation of new information and telecommunication technologies has made it possible to solve in a new way the problems of coordinate-time support
Significant results achieved on the creation of the Fundamental Astro-Geodetic Network (FAGN), improvement of methods of its construction, and increase in accuracy of coordinates by the introduction of new technologies of measurements and collocation with the existing stations of the International Global Navigation Satellite System (GNSS) network (Kitab, Tashkent, Maydanak and Maidantal)
To evaluate how accurately the conversion itself is performed, the State Geodetic Network (SGN) stations coordinates in Fergana valley were transformed from Coordinate System 1942 (CS42) to WGS84

Summary

Introduction

The implementation of new information and telecommunication technologies has made it possible to solve in a new way the problems of coordinate-time support. The national height system of the country is the Baltic normal height system It was adopted in 1977 and referenced to the mean sea level with zero-mark of the Kronstadt tide gauge in Pulkovo. To make the most of the geodetic and cartographic potential that was created so far, the task arose of providing users with methodology and data to facilitate the transformation of coordinates between the local СS42 and WGS84 ellipsoid based geocentric coordinate system. The procedure for constructing a displacements grid from the CS42 coordinate system to a new geocentric system based on the WGS84 ellipsoid using data from the new GNSS network of Uzbekistan is considered. The grid was used to update topographic maps at a scale of 1: 100 000 of the Fergana Valley

Data handling

Generation of the shift grid

Test area

Results and discussion

Conclusions