Precision Agriculture, 1, 53᎐66 1999
ᮊ 1999 Kluwer Academic Publishers. Manufactured in The Netherlands.
Remedial Correction of Yield Map Data
SIMON BLACKMORE AND MARK MOORE firstname.lastname@example.org
The Centre for Precision Farming, Silsoe College, Cranfield Uni
ersity, Silsoe, Bedford MK45 4DT, UK
Abstract. Many yield maps exhibit systematic errors that attenuate the underlying yield variation. Two
errors are dealt with in detail in this paper: those that occur when the harvester has a narrow finish to a
land and those that occur when the harvester is filling up at the start of a harvest run. The authors
propose methods to correct or remove erroneous data by the use of an expert filter, or alternatively use
of an interpolation technique called potential mapping.
Keywords: yield maps, errors, expert system, potential mapping
Commercial yield mapping systems have been available since 1992 and to date
there are more than 200 yield mapping systems fitted to combine harvesters in the
UK. All of the maps exhibit unwanted artefacts, introduced by the harvester itself
or the way in which the harvester was used. The resulting yield map not only shows
the yield variation across the field but also characteristic errors. As these maps are
now used for management purposes and decisions are being based on the variabil-
ity shown in these maps, it is incumbent on those concerned with the preparation
of the yield maps that these errors are kept to a minimum.
The objectives of this paper are to:
1. Review the identified errors and their significance on the resulting yield map.
2. Outline a number of methods for removing these errors.
The data used in this paper pertain to a field called Far Sweetbrier, on Shuttle-
worth Farms, Bedfordshire, England.
Review of errors and their significance
There are a considerable number of systematic errors that are introduced into the
yield data set. Some of them have been correctly accounted for in the yield
mapping software, others have appeared as significant errors in the resulting maps.
Moore 1998 gathered data from a number of trial fields that were yield mapped
over a period of six consecutive years. The analysis identified the following errors