1. At a mobile device communicatively coupled to a remote computing system, a method comprising: capturing imagery of an area at which the mobile device is located; performing at least one image-based privacy filtering process using the captured imagery to generate filtered imagery; determining a set of spatial features in the filtered imagery; selecting a subset having fewer spatial features than the determined set of spatial features for inclusion in an area description file, the subset based on a maximum spatial feature density criterion; and transmitting the area description file representative of the subset having fewer spatial features than the determined set of spatial features to the remote computing system.