This thesis is focused on quality issues of spatial data. The primary objective is user testing and consecutive optimization of newly created visualization for expression of uncertainty. The another content of the thesis are newly created cartography symbols for visualization of uncertainty. Map styles were also analysed, focusing on legend’s form. For evaluation of the appropriateness for the proposed methods were used the user’s testing, in form of the questionnaire and eye-tracking experiment. The results contain evaluated parameters based on user’s sensational suitability a cognitive metrics. Based on these, the optimal methods and map’s styles for visualization of uncertainty were selected considering the intuitiveness. Also, the thesis summary the results of the studies engaging this matter.