Abstract. Current commercial mobile navigation systems often use a predetermined scale selection schema without considering differences in spatial complexity of locations. To identify what map scales people may need and what spatial features make relevant maps stand out, we conducted an experiment on subjective map selection in a route planning task between two cities in the United States. Our results suggest that the distribution of selected maps is fairly concentrated on those maps that contain spatial information about both the origin and the destination, the current location and the destination, and the transition between different important roads in a route. These results suggest that the choice of map scales should not follow a preset scale rule for diverse locations, and instead, it should be adaptive to the complexity of local roads and decision-making processes.