98
To summarize, the presented method has the following
advantages:
1. It is relatively fast.
2. It enables a flexible combination of automated
learning with the existing background knowledge.
3. It exploits information contained both in the
continuous and discrete GIS attributes while no
assumption regarding the distribution of the GIS data
is made.
4. Hypotheses in the form of classification rules can be
quickly examined and their errors visualized.
5. Once the decision trees are defined, the periodical
updating of the map should be easier.
The presented method has the following drawbacks:
1. The classification accuracy depends also on the
analyst's knowledge of the study area.
2. Many explanatory GIS data layers are necessary.
3. Although being simple in principle, it is technically
complicated to implement because of the wide
spectrum of necessary tools.
4. The method does not provide means for accounting
for the uncertainty in the input data.
The first step decision tree:
UNSUPERVISED_RESULT = Forest:
. .PROX_LAKE = 0 :
:..TM5 <= 43: Water
: TM5 > 43 : Marsh
PROX_LAKE > 0 :
:..SLOPE > 0: Forest
SLOPE = 0 :
:..TM5 <= 50: Forest
TM5 > 50: Marsh
UNSUPERVISED_RESULT = Farmland:
.FOREST81 = Forest:
:..NDVI <= 211: Farmland
: NDVI > 211: Forest
FOREST81 = Non-forest:
:..NDVI > 156: Farmland
NDVI <= 156:
:..PROX_SET_HW <= 51: Unvegetated
PROX_SET_HW > 51: Farmland
UNSUPERVISED_RESULT = Marsh:
. SLOPE = 0 :
:..TM5 <= 50: Forest
: TM5 > 50: Marsh
SLOPE > 0 :
: . .PROX_LAKE = 0 :
PROX_LAKE
:..TM5 <=
TM5
Marsh
0 :
69 : Forest
6 9 : Shrub
UNSUPERVISED_RESULT = Unvegetated:
..PROX_SET_HW > 195: Farmland
PROX_SET_HW <= 195:
:..PROX_SET_HW <= 25: Unvegetated
PROX_SET_HW > 25:
:..NDVI <= 105: Unvegetated
NDVI > 105:
:..PROX_LAKE = 0: Water
PROX_LAKE > 0: Farmland
UNSUPERVISED_RESULT = Shrub:
.-..FOREST81 = Forest: Forest
:..TM5 <= 75: Forest
: TM5 > 75: Shrub
FOREST81 = Non-forest:
:..SLOPE = 0:
..PROX_WATER = 0: Marsh
PROX_WATER > 0:
:..NDVI <= 204: Marsh
NDVI > 204: Shrub
SLOPE > 0:
:..PROX_SET_HW <= 430: Farmland
PROX_SET_HW > 430:
:..POP_DENSITY <= 64: Shrub
POP_DENSITY > 64: Farmland
The second step decision tree:
TREEl_RESULT = Forest:
:..PROX_LAKE > 0: Forest
: PROX_LAKE = 0 : Water
TREEl_RESULT = Farmland:
.NDVI <= 190: Farmland
NDVI > 190:
:..TM5 <= 81: Abandoned_pasture
TM5 > 81: Farmland
TREE1_RESULT = Water:
:..FOREST81 = Non-forest: Water
: FOREST81 = Forest: Forest
TREEl_RESULT = Marsh:
:..FOREST81 = Forest: Forest
: FOREST81 = Non-forest: Marsh
TREE1_RESULT = Shrub:
:..TM5 <= 80: Shrub
TM5 > 80: Abandoned_pasture
Table 5: The two successive decision trees for reclassification of the (intermediate) unsupervised classification results