The objective of this research is to develop a field improvement based on methodology for working chracteristics on harvesting, and GIS maps using terrain information. To generate a GIS map based on the working chracteristics on harvesting and terrain information, location of the field is essential; therefore a real time kinematical global positioning system (RTK-GPS) was used to provide terrain information and also the vehicle's absolute positions. An inertial measurement unit (IMU) was used to provide posture (yaw, pitch and roll) of the tractor. The system was built on a robot tractor modified a 56kW tractor. As the result, the area where work characteristics have to be improved was identified automatically by the discriminant analysis using explanation variable of synthetic vector and inclination angls.