45
Row- and
Column-
Doubling
Rectification and
Resampling with
Bilinear Inter
polation
Classifi
cation
results of doubled
and geometrically
:ied Data
Doubled
2d
4.03
9.02
8.25
28.54
34.90
15.04
I (%)
lich disappear in
result of doubled
ling of data before
ment of classifica-
lds of data prepro-
the results. The
ns are briefly dis-
influences of the
rast enhanced data
: linear histogram
;d out separately,
neighbourhood re-
ange in respect to
is is valid for re-
nhanced data.
interpolated data
t to the result of
l occurs in isolated
classes with a lot
of highly structured areas show the greatest chang
ing. The use of contrast enhanced data for rectifica
tion and resampling instead of original data seems to
show a slightly better accuracy.
Classification of resampled data by bilinear interpo
lation may be improved if a row- and column
doubling before rectifying is carried out.
The above experiences indicate that contrast enhancement
influences classification results slightly, either if data are
geometrically preprocessed or not. Moreover classification
of nearest neighbour resampled data leads to a result,
which is only little influenced by preprocessing, even if a
great geometric transformation (from satellite image to
map grid) is performed.
If bilinear interpolation for resampling is used the classi
fication results will tend to more differences in respect to
those of the original data.
Bilinear interpolated data may be used for classification
if a doubling of data before rectifying is carried out. The
improvement of classification result is obvious, but study
ing of classification accuracy needs more detailed investi
gations.
In the whole, the investigations dealed in this paper show
the influences of various preprocessing methods. Therefore
the purposes for the digital classification of different kinds
of image preprocessing must be considered carefully.
REFERENCES
Forster, B.C., Trinder,3.C., 1984. Effects of Resampling of
Landsat Data on Classification Accuracy. Aust. Л. Geod.
Photo. Surv., 40, Липе 84: 53-67
Kähler, M., Milkus, I., 1986. Berlin from Space - A Digital
ly Produced Satellite Image Map. Intern. Symp. on
Mapping from Modern Imagery, Edingburgh September
1986 (in print)
Realnutzungskartierung und Flächenbilanzierung, Maßstab
1:50000, im Bereich des Raumordnungsverbandes Rhein-
Neckar. ifp-Institut für Planungsdaten und StadtBauPlan
Frankfurt am Main/Darmstadt 1976