Coordinate calculation method

A touch panel detects a point in one of a plurality of unit areas at which an input was made, the unit areas being arranged in a matrix in an instruction plane. A game apparatus repeatedly acquires detection coordinates for locating a unit area detected by a pointing device. Also, the game apparatus repeatedly calculates, in response to the acquisition of the detection coordinates, detailed coordinates by which a point can be represented with accuracy in more detail than by the detection coordinates. The detailed coordinates indicate a point in the direction of a unit area indicated by previously acquired detection coordinates, as viewed from a predetermined reference point within a unit area indicated by currently acquired detection coordinates.