Display system in an excavator and method for controlling same

A display system in an excavator for displaying a guidance picture showing a current position of the excavator and a display object surface indicating a part of a target land shape of an object of excavation, the system comprising:

• a storage unit configured and arranged to store land shape data indicating a position of the display object surface;
• a position detector unit configured and arranged to detect a current position of the excavator;
• a calculation unit configured to
• set a predetermined display range displayed as the guidance picture for the land shape data,
• calculate a position of an upper boundary line indicating a height of a top of a cross section of the display object surface and a position of a lower boundary line indicating a height of a bottom of a cross section of the display object surface based on the land shape data and the current position of the excavator, and
• set a predetermined reference point of the predetermined display range based on a positional relationship in an up-and-down direction between the current position of the excavator and the upper boundary line or between the current position of the excavator and the lower boundary line;
• and
• a display unit configured and arranged to display a guidance picture showing a cross section of the display object surface included in the predetermined display range as seen from a side of the excavator, and the current position of the excavator.