A method includes obtaining a destination of a user of a terminal device, and setting an exposure time of an image sensor included in the terminal device so that, in an image obtained by capturing a subject by the image sensor, a bright line corresponding to each of a plurality of exposure lines appears according to a change in luminance of the subject. The method also includes obtaining a bright line image including a plurality of bright lines, by capturing the subject that changes in luminance by the image sensor with the set exposure time, and obtaining identification information of the subject, by demodulating data specified by a pattern of the plurality of bright lines. The method includes obtaining a position of the terminal device, and displaying an arrow that indicates a direction from the position of the terminal device toward the destination on a map on the terminal device.