With a registration function, a terminal device sends shooting-location information and a landmark name to a server. The shooting-location information is obtained from an image file, and the landmark name is inputted by a user. The server registers the received location information and the received landmark name in a database so as to relate them. With a retrieval function, the terminal device sends the shooting-location information to the server. On the basis of the received location information, the server retrieves one or more corresponding landmark names along a high-accuracy retrieval program. The retrieved landmark name is sent to the terminal device.