DIGITAL TOPOGRAPHIC MAP ACCURACY ASSESSMENT AND OPTIMIZATION: A CASE STUDY OF SIRDARYA REGION, UZBEKISTAN (SCALE 1:50,000)

• Bosimova Diyora

  Gulistan state university 32-25 group 1st year student dbosimova1@gmail.com

  Author

Accurate digital topographic mapping plays a fundamental role in national spatial planning, geo-monitoring, water management, land cadastre systems, and infrastructure development, particularly in regions where economic productivity depends on land and water resources. Despite continuous progress in Geographic Information Systems (GIS), remote sensing, and cartographic data processing, the challenge of positional error minimization remains critical in developing countries, including Uzbekistan. This research provides a methodological, statistical, and comparative evaluation of digital topographic map accuracy at a medium-scale resolution of 1:50,000, with a specific focus on Sirdarya Region. The region presents a suitable case due to its intensive irrigated agriculture, vulnerable soil salinity conditions, and frequent land-use changes. Data accuracy is assessed through Root Mean Square Error (RMSE), Circular Error at 90% confidence (CE90), and Linear Error Probability (LEP), using control points extracted from GNSS measurements, Copernicus DEM, and high-resolution Sentinel-2 imagery. International datasets including USGS, NASA EOS, and ESA Copernicus are compared to national cartographic products. The results reveal significant positional deviations ranging from 4.1 to 21.6 meters, depending on land cover type, vector feature class, and interpolation method. Based on these findings, optimization strategies are proposed through enhanced GNSS integration, AI-assisted feature classification, adaptive DEM interpolation, and geodatabase standardization. The research concludes that the optimal improvement approach involves hybrid RS-GIS processing combined with regulated national standards, which can drastically decrease positional uncertainty while enabling high-fidelity national mapping for long-term land management.

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