Urban environments require cognitive abilities focused on both spatial overview and detailed understanding of uses and places. These abilities are distinct but overlap and reinforce each other. Our work quantitatively and qualitatively measures the effects on a user's overall understanding of the environment after navigating with either a GPS or a road map in a previously unknown neighborhood. Experimental recall of spatial and semantic information indicates that using a road map enables subjects to demonstrate a significantly better spatial understanding, identify semantic elements more often using common terms, place semantic elements in spatial locations with greater accuracy and recall semantic elements in tighter clusters than when using a GPS. We conclude that a spatial understanding is a necessary framework for organizing semantic information that is useful for inferred tasks. Categories and Subject Descriptors H.5.2 [Information Systems]