Development of Topographic Maps for Precision Farming With Kinematic GPS

The objective of this study was to examine the potential to use real-time kinematic differential GPS (RTK-DGPS)to collect GPS data on a moving vehicle for the development of topographic maps. An intensive study on a 1.5 ha field on anapproximate 3 m grid spacing was first conducted, using two GPS data collection modes, stop & go (using a tripod GPSantenna mount) and kinematic (with tractor mounted GPS antenna). It was found that the standard deviation of the elevationerror between 10 true error points and the calculated topographic surface ranged from 2 to 3 cm for data collected on anapproximate 3 m grid. The elevation error for derived grid spacings of 9, 18, and 33 m ranged from 2 to 5 cm. On a second20 ha field, only RTK-DGPS data was collected on an approximate 10 m grid spacing, with a resulting elevation error of4 cm using stop-and-go true error points, and 6 cm using RTK-DGPS true error points. A third 115 ha field was studied bycollecting data on an approximate 30 m grid with RTK-DGPS, with a resulting elevation error of 9 cm. The results arepositive and indicate that the technique of collecting RTK-DGPS data on a moving vehicle is a viable means by which datacan be collected to quickly develop topographic maps for precision farming and other applications.