Time shift evaluation to improve yield map quality

John P. Beal, Lie F. Tian

Research output: Contribution to journalArticlepeer-review


Quality data sets are essential for precision farming. Yield monitor data sets have to be processed to coordinate yield information with the proper geographic references because of time delays involved with threshing the crop and receiving the yield information. The time shift needed to account for these delays was shown to vary from 8 to 14 s. Yield data generated by three different combines in corn and soybeans were tested with a range of time shifts. Conventional yield maps were also processed to evaluate the results. A value termed surface area ratio (SAR) was developed to determine the best time shift for the data. SAR is the ratio of the upper surface area of a 3-D yield map to the projected area of that yield map. All of the data sets produced a localized minimum value of SAR at a time shift that also produced a conventional yield map with the best visual interpretation. The time shifts, as determined by the minimum SAR, varied by combine. SAR appears to be a valid method for determining the correct time shift for yield sensing systems.

Original languageEnglish (US)
Pages (from-to)385-390
Number of pages6
JournalApplied Engineering in Agriculture
Issue number3
StatePublished - May 2001


  • Global positioning systems
  • Precision farming technology
  • Site-specific crop management
  • Yield maps
  • Yield monitors

ASJC Scopus subject areas

  • General Engineering


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