Geographic information of field, which consists of geographical position, shape and area, is one of the most basic information in precision agriculture. Fine fertilizer, irrigation and yield estimation of crops are determined by one of those information.
the shape and area of the field, which is also the main basis of the charge of agriculture machinery working. The conventional measurement for field is using tape manually which is suitable for small and regular field. ฺBut it will be time-consuming and complex when measuring large or irregular field. GPS can provides location and navigation information such as real-time longitude, latitude, elevation and so on. It is one of core technology that support precision agriculture practice. Some people like Qiu ZL used uPatch022L type GPS model, 89s52 MCU etc to design a instrument to measure area of farmland. It adopted trapezoidal algorithm to calculate area, offering a new way of rapid farmland area measurement. To satisfy the needs of agricultural machinery operation charge according to area, This paper proposes an agricultural farmland valuation instrument adopting cheap UP500 type GPS model and C8051F020 MCU of high performance-price ratio. In the algorithm, the optimized triangle algorithm is used to calculate area. The function of valuation according to area is designed based on this. Experiments and research of this design valuation instrument are taken. The experiment proves that this instrument can realize rapid and real-time measurement of farmland area under certain precision and calculating the total price