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In comparison to wheat, sugar beets do not reach such a striking increase in
the plant mass above ground . This is why they can be separated so well
(Kuehbauch, 1990) .
For the latter two land uses it is of advantage that settlement areas and opencast
mining areas were masked out, since they would otherwise spectrally
compete with each other . The producer's accuracy of raised bog (RB,
97.69 %), deciduous forest (DF, 95.75 %) and grassland I (GL I, 95.06 %) also
still provides very good results, but a few pixels are already assigned to other
classes here. Few of the pixels actually belonging to the category of potatoes
(PT) are classified as grassland I, which results in an accuracy of 94.37 %.
Fallow land (FL, 92.77 %) mainly overlaps with maize, grassland II (GL II,
92.45 %) mostly with vegetables . Nevertheless, the results are still to be denoted
as good . The producer's accuracy is no longer sufficient for barley (BR)
with 74.68 % and insufficient for fruit (FR) with 61 .52 %. 24 % of the reference
plots on which barley is grown are identified as sugar beets . 38 % of the fruit
growing areas are identified as grassland . The omission error is thus much too
high .
Although the individual channels of LANDSAT ETM+ cover a relatively broad
wavelength range, species recognition can be performed well after the transformations
described . Problems are posed by the heterogeneity within the
intensively cultivated areas of the loess regions, which, however, was adequately
identified . Furthermore, the cultivation in narrow plots poses some
difficulties . Narrow strips, for example, cannot or can only be wrongly identified
due to the mixed pixel problem .
6.3.4 Disaggregation
On the basis of the supervised classification of the LANDSAT ETM+ scene of
26 June 2001, the disaggregation of the nutrient balances is now performed
using the example of nitrogen and the maximum likelihood classifier after filtering
by probabilistic label relaxation . Since not all crop species listed in the data
of FAA Bonn can be separated, several species must be combined . For example,
the land use classes of meadow and pasture, which cannot be differentiated
by remote sensing data, are averaged in a weighted manner and allocated
to the grassland category on the basis of an agricultural structure survey
by the State Agency for Data Processing and Statistics NRW (Landesamt für
Datenverarbeitung and Statistik NRW, 2001) of the year 1999 .
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