Nowadays, various types of geodetic measuring instruments are available in surveying. When conducting a survey of a terrain, surveyor must choose a survey method that is capable of providing high precision measurements. In the surveying process, it is possible to use the following measurement methods − tachymetric survey method, positioning method and remote sensing method. Each of the methods produces data formats that can be used further for volume calculations. The paper analyses the volume differences that are obtained when using various survey methods and volume calculation programs to obtain the surface model. The use of such a tool is important for useful mineral miners, so that surveyors make qualitative surveys and obtain accurate and reliable volumes. Useful minerals miners are required to report annually on their mining volume for a specified period. The useful minerals miners shall at all time keep records of the quantities of minerals actually extracted. Regardless of the type of accounting, topographic surveying and the calculation of volumes, if mineral is extracted in mineral deposits of national importance, more than 50 000 m**3, are required (Augstas detalizācijas topogrāfiskās…, 2012). High-quality and accurate topographic survey is needed to create the most realistic surface model appropriate to the terrain. It is defined that the difference between the volumes obtained from the recording of vehicle loads should not be more than 5% when comparing the result of the mineral extraction from topographic surveys (Derīgo izrakteņu ieguves…, 2012; Noteikumi par valsts…, 2018). Nowadays, various measurement methods can be used to obtain data from which a surface model can be generated, and this model can then be used for volume calculations. The surface model is a set of points where, in addition to plane coordinates (x and y), there is also altitude (z) known (Luukkonen, 2011). Each measurement method has its own different measuring instruments that can be used, each method has its own operating principles, on which the quality and accuracy of the obtained data depends.

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.