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information among different organisations is steadily
increasing, this latter subject might be of great importance
for further studies.
When using the K-L expansion, the data is reduced with
minimum . loss of information. For terrain classification
purposes, other criterions should also be fulfilled, for
instance that the characteristic parameters are easy to
derive and that they are easy to use for different purposes.
These considerations have not been treated in this study,
but are necessary for a model for terrain classification.
The model must also be valid for a large number of different
terrain types. In this study, only six terrain types from
northern Europe have been used. This is of course a severe
limitation and before any recommendations concerning a world
wide model for terrain classification can be made, a larger
sample is needed.
5. CONCLUSIONS
On the basis of the results of this limited study, the
following conclusions may be drawn.
1.) The Karhunen-Loeve expansion is a method for data
reduction with minimum loss of information. When applied to
digital elevation data, the data may be reduced considerably
without a significant loss of information.
2.) When constructing a model for terrain classification,
the Karhunen-Loeve expansion may be used with success. But
attention should also be paid to other criterions than data
reduction, such as methods for performing and using such
classifications in real situations.
6. ACKNOWLEDGEMENT
This work has been financially supported by The Swedish
Council for Building Research (BFR), contract number
840432-2.
7. REFERENCES
Agterberg F.P, 1982. Recent developments in geomathematics.
Geo-Processing, Vol 2, No 1, pp 1-32.
Forstner W, 1983. On the Morphological Quality of Digital
Elevation Models. Proc of International Colloquium on
Mathematical Aspects of Digital Elevation Models, Department
of Photogrammetry, KTH, Stockholm.
Frederiksen P, Jacobi ©, Justesen J, 31978. Pourier-
transformation von Hohenbeobachtungen. Zeitschrift fur
Vermessungswesen, Heft 2, pp 64-79.
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