Computer System, Computer System Control Method, Program, And Information Storage Medium

A computer system having a coordinate designation system for producing base data for calculating position coordinates and storing a first application program, a second application program, and an operating system for activating the first and second application programs, wherein

• the first application program causes the computer system to function as
• first position coordinate obtaining means for obtaining position coordinates that are calculated based on the base data,
• first designated position image display means for showing a designated position image on a display screen based on the position coordinates obtained by the first position coordinate obtaining means,
• activating means for activating the second application program, and
• notifying means for notifying the second application program activated from the first application program of the position coordinates obtained by the first position coordinate obtaining means, and
• the second application program causes the computer system to function as
• second position coordinate obtaining means for obtaining the position coordinates that are calculated based on the base data, and
• second designated position image display means, when the second application program is activated from the first application program, for obtaining the position coordinates notified by the notifying means, and showing the designated position image on the display screen based on the position coordinates obtained, and when the second application program is activated from the operating system, for showing the designated position image on the display screen based on the position coordinates obtained by the second designated position image display means.