In recent years, True-3D representations such as lenticular visualization have entered the stage of analogue and, especially, digital cartography. The increase of 3D displays as products of mass media raises some fundamental questions about a new generation of 3D maps. Auto-stereoscopic displays allow cartographers to design 3D maps covering several information layers located at different positions along the depth axis. However, it remains unclear whether the opportunity to spread map information over different information depth layers can improve cartographic communication by helping to increase the duration and accuracy of map reading. This article presents the results of an empirical study, based on the test results achieved by 83 geography students who counted different map symbols in a series of 2D or 3D thematic maps of differing complexity.