ABSTRACTThe omnipresence of orientation, wayfinding and navigation tasks in everyday life calls for high-quality cartographic media that help people to solve their tasks in the best possible way. Modern maps should not only consider modern visualization techniques and design approaches but also knowledge on the map user’s cognitive processing. Previous studies of cognitive cartography and spatial cognition identified grids as suitable cartographic elements that can enhance the accuracy of cognitive representations of geographic space. Grid lines form grid cells and these cells subdivide a map layout into different regions. These regions seem to contribute to a categorization of cartographically represented contents. The categorical organization of a map provides a superordinate spatial structure that can improve the recall of object locations. An important parameter influencing categorization is the distance between grid lines (spacing/separation). A previous study suggested 5 cm (paper distance) spacing as being suitable for an accurate performance in recalling object locations in topographic maps. Based on a recall-memory-paradigm adopted from experimental studies in cognitive psychology, the experiments reported in the present study take up this value and aim at specifying the ideal value of grid line spacing for object location memory. The results show that previous findings can be extended. The results allow the proposal of ideal grid line spacing in a 6.5-7.5 cm range. These spacing values help to reduce spatial distortion errors in the memory of object locations, especially in maps with a low amount of visual details.