In the following diploma thesis, we compared the data from the database DTK 5 with the data from field measurement by GNSS in a selected area of forest roads of Šišenski Hill. Since the terrain measured by GNSS enables the determination of the 3D position of points, we also made a parallel comparison of heights, so that we were able to compare the interpolated heights measured by DMV 5 with the heights obtained from GNSS field measurement. The measurement was carried out in rather unfavourable conditions for GNSS and during the measurements we also compared the ability to determine positions of points with the instruments Leica Viva GS15 and Javad Triumph-LS. Despite difficult conditions, at the time of still incomplete greening of deciduous forest, we were successful at determining the position of plurality of points with usage of instrument Javad Triumph-LS. With the usage of instrument Leica Viva GS15 we were less successful. Therefore, we determined the points’ positions with a combination of GNSS and classical geodetic measurements. At the given test area, we discovered that the deviations in the horizontal plane according to DTK 5 and height deviations according to the DMV 5 are higher in areas with high vegetation. Positional differences in areas without vegetation were much less obvious.