One of the main biological-technical-economic disciplines focused on the current state, development, setting new goals (management models) and also the creation of map sheets and PSoL is forest management. The progress of GNSS development and advancement is a major prerequisite for progress in streamlining forest mapping. The aim of this work is to compare the determination of positional accuracy of two receivers (GNS2000 PLUS and Xiaomi Mi8) with and without the influence of foliage (vegetation, non-vegetation period) on two routes (meadow, forest). The issue follows the description of GNSS theory and related measurement methods together with the description of the coordinate systems WGS - 84 and S - JTSK. The work also contains a methodology associated with the evaluation and processing of collected data. The data collected by the above-mentioned devices were used to determine the results. For the GNS 2000 plus, the mean square error mxy on the forest route was 4.91 m during the growing season and 5.77 m during the non-vegetation period. With the Mi8 smartphone, a mean square error of mxy was achieved on the forest route of 2.54 m during the growing season and 2.39 m of the non-vegetation period. On the meadow route, the GNS2000 plus achieved a mean square error of 0.58 m during the growing season and 3.88 m during the non-vegetation period. With the results, I wanted to point out the possibilities of using smartphones in forest mapping. The possibility of using mobile devices is recommended mainly for the informative nature of the data, eg: mining - transport process, finding out the size of calamity areas, etc. The current progress in the development of mobile technologies suggests that in a certain period of time, the use of smartphones will be an integral part of forestry in the forest mapping industry in Slovakia.