An aspect of the present invention includes 1) a process of detecting an event input that is inputted by an operation signal and determining sound characteristic information and sound effects corresponding to the event input, 2) a process of obtaining a first sound source position coordinates information in which a location where an event occurred in a virtual space is taken as a sound source position, 3) a process of determining a propagation mode of a sound to be produced corresponding to the event input in the virtual space based on sound characteristics information and the first sound source position coordinates information, 4) a process of determining a second sound source position coordinates information indicating a position of a sound source on the radar image based on the first sound source position coordinates information, and 5) a process of displaying a sound wave image indicating a propagation mode of the sound effect on the radar image based on the propagation mode of the sound and the second sound source position coordinates information.