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Potential Application of Yield Data for Creating Topographic Maps

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Paper number  031084,  2003 ASAE Annual Meeting . (doi: 10.13031/2013.14927) @2003
Authors:   Dharmendra Saraswat, Reza Ehsani, Nathan Watermeier, Mathew Sullivan
Keywords:   Yield data, Elevation data, Vertical accuracy, Precision agriculture, RTK GPS

This study investigates the accuracy of generating topographic maps for relatively flat field using multiple years of yield monitor data collected using two different types of sub-meter level accurate differential global positioning receivers. Median filters were used to remove outlier and overlapping elevation data. Using a Real Time Kinematic GPS (RTK GPS), the actual elevation of the field was measured and a topographic map was created. Elevation collected from multiple years of yield data was filtered, averaged and interpolated employing nearest neighbor technique using 12 neighbors and cell sizes of 5, 10 and 15 m. Visual Basic macro was run to determine elevation values contained in interpolated DGPS maps that corresponds to the location of RTK GPS points. By averaging four years of elevation data, overall error could be reduced to 0.53 m from a high of 1.54 m as estimated by root mean square error (cell size =5 m for interpolation). Topographic maps generated by RTK and average DGPS depicted the relief of the field fairly accurately. Elevation difference map showed the fairly high conformity of elevation information derived from RTK and average DGPS map. Thus, topographic maps derived from yield data can also be used by producers for explaining yield variability in sitespecific farming.

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