Method and a video game system of generating a field map

A method and a video game system that are capable of generating a field map with more natural geographical feature. The method and the video game system firstly divides the field map including a plurality of blocks into a first zone and a second zone by a boundary which consists of sides and comers in the blocks, then determines a first point for each side included in the boundary and a second point for each corner included in the boundary. Finally, the boundary is transformed into a more complex land shape by connecting the first points and the second points. The video game system includes a block division unit that divides the field map into a plurality of blocks, a block assign unit that assigns each of the divided blocks to either a first zone or a second zone using a boundary that consists of sides and comers of the blocks, a first point determining unit that determines a first point for each side, a second point determining unit that determines a second point for each corner, and a transforming unit that transforms the boundary by connecting the first points and the second points.