Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.
Development of Agricultural Field DEM Using Repeated GPS Measurements from Field Operations: Effects of Sampling Intensity and Pattern
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: 2007 ASAE Annual Meeting 071089.(doi:10.13031/2013.22908)
Authors: Samsuzana Abd Aziz, Brian L Steward
Keywords: Digital elevation model, GPS, topography, intensity, pattern, grid size
Widespread used of GPS systems in agricultural vehicle allows farmers to collect elevation data repeatedly to develop field-level DEM. Accuracy of these DEMs can be improved by understanding how errors are introduced from sampling procedures. In this research, a 120 m by120 m test field was modeled using a 10-m-grid USGS DEM of Winneshiek County, Iowa. Multiple sets of vehicle-based GPS elevation measurements from four filed operations (tillage, planting, spraying and harvesting) with different swath width and speed level were simulated using inverse distance weighting (IDW) interpolation from the test field. GPS errors were modeled using Gauss-Markov process and added to the simulated measurements. Then DEMs were created using a method proposed by Aziz et al. (2005). Results show that RMSE gradually decreased as the number of measurement sets used increased and leveled out after approximately 12 measurement sets unless an increase in input resolution of the elevation data were introduced to improve the RMSE of the resulted DEM. For the widest swath width, as the speed level (distance between data points along a track) decreased, the RMSE decreased from 0.23 m to 0.16 m. Track patterns on the other hand, had significant effects on the topographic maps if very small grid size is used to generate the DEM.(Download PDF) (Export to EndNotes)