A device obtains at least one characteristic of at least one radio signal detected at a mobile device that is located at a particular site and a representation of a radio environment for the site and a definition of at least one specified path section for the site. The at least one path section has been specified by a person in a map presented on a display. The device determines a location estimate for the mobile device based on the at least one characteristic of the at least one radio signal and based on the representation of the radio environment for the site and adjusts the determined location estimate based on the definition of at least one specified path section.