ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
402
which accounts for 76% of accuracy. Conventional soil maps
typically achieved 60-70% of accuracy. The 50 sites can be
divided into two groups: one on the drumlin areas and the
other on the inter-drumlin areas. The accuracy for the sites in
the drumlin areas reaches 90% while the accuracy for the
inter-drumlin areas is about 63%. The difference in accuracies
between the two areas is due to the difference in
environmental gradients and the fact that SoLIM is sensitive to
the ability of characterizing soil formative environmental
conditions. The relief (gradient) in the drumlin areas is much
stronger than that over the inter-drumlin areas. For the drumlin
areas, the soil formative environment conditions for different
soils can be easily distinguished (characterized) using GIS due
to the stronger relief. As a result, the soil-landscape model is
more ‘faithful” applied through SoLIM. However, the soil
formative environment conditions for different soils in the inter-
drumlin areas is very difficult to distinguish due to low relief
and it is difficult to distinguish soils over these areas using the
environment conditions. Overall, we believe that the soil-
landscape model developed through the use of FCM
methodology is of good quality since the accuracy of the soil
map exceeds that of common soil maps produced through
extensive soil surveys.
Legend
Kidder
McHenry
St.Charles
Mayville
Virgil
Sable
Figure 2: Soil map produced from SoLIM using the soil-landscape model constructed using the FCM-based method.
4. Summary
This paper presents a methodology to assist the development
of knowledge of relationships between a given geographic
phenomenon and its environmental conditions. The method
employed a fuzzy c-means classification to identify unique
combinations of environmental conditions and to discern
locations of these unique combinations. The results (the
unique combinations and the spatial locations of these unique
combinations) were then used to direct field investigation
efforts and to improve the efficiency of acquisition of
knowledge on the relationships in the field.
Through a soil mapping case study it was found that the FCM
assisted field investigation was effective in developing the
knowledge of the soil-environmental relationships. First, the
amount of field observations was reduced. Second, the
acquired knowledge of the relationships was of high quality.
Acknowledgements
The research reported here was supported by a research grant
from the Graduate School, University of Wisconsin-Madison,
by the funding from Natural Resource Conservation Service,
United States Department of Agriculture under Agreement No.
69-5F48-9-00186. The State Key Lab of Resources and
Environmental Information System (LREIS), Institute of
Geography, Chinese Academy of Sciences kindly provided
travel support to the senior author to attend this meeting.
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