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multispectral data
maximum
likelihood
; digital landscape
panchromatic model
classification classification
n s à settlement
2 probability
or^ &
|" probability
ie —
situation forest
forest
laver layer
_-- BB
Rule-Base
with conditions
Fig.l: Flow chart diagram
Landuse
Fig. 1 shows the flow chart diagram of the complete
classification procedure. As a result we obtain the
landuse-layer at a spatial resolution of 15 m x15 m with a
class and a reliability code assigned to cach pixel of the
landuse image.
8 EXAMPLES
5.1 Thematic Mapper + IRS-1C-pan
In a practical test example we combined a Landsat TM
image with an IRS-1C-Pan image. The acquisition dates
were 1991 and 1996. respectively. The TM image was
Fig.2: IRS-1C-pan original and sigma filtered
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
classified as described in chapter 2. As a result we obtain
the two classifications with the highest and the second
highest probability. By comparing the two results it is
obvious, that "Water", "Forest" and "Grassland" are quite
certain classes, while the difference between the two
classifications for "Fields" and "Settlements" is not
significant shwoing that these two classes are relatively
uncertain. We shall pay attention to that fact when these
data are combined in the rule based classifier.
The panchromatic image IRS-1C-Pan turned out to be
rather noisy. Filtering the image in advance seemed to be
advantageous. In order to leave the edges and the textural
image properties unaffected as much as possible (they
bear valuable information necessary for texture analysis)
Fig. 3 Detected points and edges and the settlement class