on one data source only. Exceptions to this were four rules
based on both preclassification result and height data, which
were needed to distinguish quarries from other open areas.
Examples of rules based on the preclassification result are
presented in Table 2. All the rules derived from the old land use
data are presented in Table 3 and all the rules derived from the
height data in Table 4.
Condition
If ML-class is fishpond
If ML-class is fishpond
If ML-class is fishpond
If ML-class is fishpond
If ML-class is water
If ML-class is garden
If ML-class is garden
If ML-class is garden
Action
Confirm fishpond 0.50
Confirm water 0.30
Confirm garden 0.10
Confirm open 0.05
Confirm water 0.90
Confirm garden 0.65
Confirm forest 0.20
Confirm rice 0.10
Table 2. Examples of rules and believes determined from the
preclassification result.
Condition
If land use is water
If land use is cultivated land
If land use is cultivated land
If land use is cultivated land
If land use is cultivated land
If land use is forest
If land use is forest
If land use is forest
If land use is urban
Action
Confirm water bodies 0.9999
Confirm field 0.60
Confirm water bodies 0.10
Confirm urban area 0.15
Confirm open area 0.15
Confirm forest 0.50
Confirm urban area 0.20
Confirm open area 0.30
Confirm urban area 0.9999
Table 3. Rules and believes determined from the old land use
data.
Condition
If height < 10 m
If height > 10 m
If height > 10 m
If height < 25 m and
ML-class is open
Action
Disconfirm forest 0.90
Disconfirm water bodies 0.70
Disconfirm field 0.80
Confirm open 0.70
If height < 25 m and Confirm quarry 0.05
ML-class is open
If height > 25 m and Confirm open 0.25
ML-class is open
If height > 25 m and Confirm quarry 0.50
ML-class is open
Table 4. Rules and believes determined from the height data.
Combination of evidence. When all the belief values that the
rules give for a particular segment or pixel have been assigned
to classes, the evidence is combined using the Dempster-Shafer
method for hierarchical cases. The method calculates a final
belief value for each class in the hierarchy taking into account
the belief values of the whole tree. In this study, the segment or
pixel was classified as the terminal class having the highest
final belief.
4. RESULTS
4.1 Maximum Likelihood classification
Result of the Maximum Likelihood classification for a subarea
of size 11.7 km x 13.75 km is presented in Figure 4. The
confusion matrix of the Maximum Likelihood classification can
be seen in Table 5. The classification was segment-based
(Figure 3).
E ó d Ea 1
CADRE Bp 5
SRE Wa Hg GER
JEBEL Bl I
| "e t
Rh
Sepik
[ela] DY
Urban and open areas
T Water
Figure 4. Result of the segment-based Maximum Likelihood
classification.
Forest
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996