Local geodetic network is very important in harmonic development of city territory. On the base of the local geodetic network, cadastral and topographic surveying works, engineering geodetic works and executive measurements of newly built buildings and engineering networks are carried out. In the territory of Riga, the local geodetic network was started to create in 1880, and in the course of time, as the city expanded, necessity to have wider reference network emerged. In 2005, in the territory of Latvia, network of continuously working base stations LatPos was launched, which ensured completely new trends in execution of measurements and accuracy reached. One year later, base station network EUPOS-RIGA was launched in the territory of Riga. It can be regarded as consistent part of Riga local geodetic network. The purpose of the research was to state, what are differences between historically used coordinates of points of the local geodetic network, and coordinates that are determined by use of real time corrections of LatPos and EUPOS-RIGA base station network. Measurements were made in the territory of Riga in period from December 2016 until April 2017. In the framework of the research, 61 point of the local geodetic network was inspected and in 38 cases GNSS observations in RTK mode were completed. In the research, catalogues of coordinates of polygonometry points of sixties and eighties were used in order to compare what differences of coordinates existed historically. The main conclusion drawn during the research – historical points of the local geodetic network shall not be used for surveying works of any kind before improvement of them and before they comply with requirements of normative acts.

The presence of a large number of territorial units with a high price of land determines the appropriate accuracy of their area determination in the short term. The widespread use of unmanned aerial vehicles (UAVs) is a modern geospatial mapping technology. Using an UAV equipped with appropriate devices for aerosurveying − such as, for example, the Trimble UX5 − is economically feasible in comparison with ground geodetic measurements, since the latter requires a lot of costs. Therefore, the main purpose of this study is to analyze accuracy estimation of land parcel area determination based on aero surveying materials using an unmanned aerial vehicle (UAV) in comparison with results of ground geodetic measurements using a total station. As a result, a comparison of detailed plan and an existing base of land parcel measurements with accuracy estimations have been made. Based on our analysis and experimental studies, we can state that the UAV allows more efficient data collection within the requirements of land management in comparison with ground geodetic measurements. The use of aero surveying materials for determination of land parcel areas has been proposed. The results of the study provide an opportunity to improve the reliability of land parcel data in the normative and methodological framework.

The systemized and methodically arranged according to the principles of geographic information systems set of the most important objects of Lithuanian territory’s geodetic base and topographic databases (GDR10LT) is collected and kept in data storage and covers the whole territory of Lithuania. The purpose of the georeferential base GDR10LT at the scale 1:10 000 is to collect, keep, use, renew and provide data to users. The literature analysis shows that the majority of authors presented studies about data composition and application but they did not analyse their reliability. The aim of the research was to revise the chosen territory of the georeferential base map by the field method and to determine the discrepancies between the situation in the area and in the map as well as the reasons of such discrepancies. It was necessary to verify the data reliability and outdated map information due to changes of the situation. The field research was conducted in three different areas, and the data was processed using tools provided by www.zis.lt. Statistical data analysis was performed using Microsoft Excel software. The object of the research was information depicted in georeferential base map (GDR10LT) of the chosen territories. The following research methods were used: literature analysis, analysis of cartography material, collation of field data, statistical data processing, and interviews. The conclusion can be made that GDR10LT data are reliable; two mistakes were found in the plot of 6407.5 hectares: a navigational obstacle and 800 metres of asphalt cover were not marked. Other determined discrepancies covered the territory of 17.46 hectares. The outdated map information was found. The marking of settlements generally were mismatched because of many new buildings in the area that were not mapped. Therefore GDR10LT should be updated more often in accordance with ORT10LT data.

Spatial data is constantly evolving, and the accuracy of spatial data is constantly changing. The latest GRPK and orthophotographic map were used in the study. Accuracy is also affected by technological advances, which are driven by improvements in working methods, which include the development of work tools and the development of data sets that contain structured data. The data contained in the data sets are determined by a variety of methods, such as field measurements (GPNS receiver or tacheometer) and analysis of digital photographic images, which are determined using aircraft or satellite systems. The determined data is processed with the help of specialized software, which is selected depending on its functionality and capabilities, and with the help of which the determined data is processed as accurately as possible. Accurate spatial data in densely populated areas makes it easier to carry out planning and design work correctly. The study is performed to determine the accuracy of the coordinates of the selected structures using remote methods. The more similar studies are conducted, the more confident the GRPK data generated remotely will be of the required accuracy, reliability, and applicability to planning, forecasting, and other important tasks. The article compares geodetic measurements and GRPK data and geodetic measurements and ORT10LT data, identifies coordinate differences, the size of the discrepancy and its average, and calculates the root mean square error. The object of the research is spatial and cartographic data of different buildings. The aim of the research is to determine and evaluate the accuracy of the coordinates obtained using remote sensing methods.