Positional accuracy control of national orthophoto with GNSS positioning

Orthophoto is very popular among the users, but its quality is not regulated, since there is no mandatory quality control standard existent in Slovenia. Quality check is performed systematically during the implementation of the project of the Cyclic Aerial Survey of Slovenia and with the support of the scientific and technical report (Kapnias et al., 2008). A number of standards are being used abroad to control the positional accuracy of spatial data, among which the most relevant are the National Standard for Spatial Data Accuracy (NSSDA) and the Standardization Agreement 2215 (STANAG 2215). Since both standards differ considerably in the size of the sample and the statistical model, they were put to test in the master thesis by using them to control the quality of the national orthophoto from the 2014 time series in the trigonometric district of Celje. The orthophoto and stereopair control points were measured and reference values were obtained by the GNSS RTK method. Data was processed by using the methodology of both standards and the standards were subsequently evaluated. Orthophoto was produced for two sections by using DMR 1 obtained from the laser scan data, and the reduction in variation at control points was examined. The results were interpreted and STANAG 2215 was suggested as the national standard for measuring the quality of positional accuracy of orthophoto in Slovenia