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4.4 Classification System
Certain classification schemes have been developed that can
readily incorporate land-use and/or land-cover data obtained by
interpreting remotely sensed data (e.g., U.S. Geological Survey
Land Use/Land Cover Classification System, U.S. Fish &
Wildlife Service Wetland Classification System, NOAA
CoastWatch Land Cover Classification System, Asian Land
Cover Classification System, etc.) (Jensen, 1996; Tateishi et al,
1995). The U.S. Geological Survey Land Use/Land Cover
Classification System was chosen and referred to form the
classification system for this study. By considering on the four
levels of the U.S. Geological Survey Land Use/Land Cover
Classification System (Jensen, 1996) and the type of remotely
sensed data typically used to provide the information, the
classification system was created as in Table 2.
Table 2. Land Cover Classification System in Ansan, Korea
Class Description
Unclassified
Forest land
Rangeland
Agricultural land
Wetland
Barren land
Urban and/or built-up land
Saltpan
Tidal zone
Water (sea and inland water body)
ojos|-31[o NH DIN =
4.5 Dataset and Algorithm Selection
The Landsat TM data of May 20, 1993 was used as the test
dataset to select the optimal dataset and most suitable
algorithm for land cover classification. Two datasets were
prepared based on the Landsat TM data of May 20, 1993, one
is subr9305.img which includes seven TM bands, and the other
is r*ndvi93.img which includes seven TM bands and NDVI.
Two training datasets, 9305-1.roi and 9305-2.roi, were
collected randomly from the false color composite image
r93fcc.img. One of the two datasets was used to perform
classification while the other was used to evaluate the accuracy
of classification maps.
The training data 9305-1.roi and the classification algorithms
PAR, MID, MAD, and MAL were used to process the datasets
subr9305.img and r+ndvi93.img, through which various
classification maps were produced respectively: r93par.cla,
rv93par.cla; r93mid.cla, rv93mid.cla; r93mad.cla, rv93mad.cla;
r93mal.cla, rv93mal.cla; r93cut.cla, rv93cut.cla, where
r93par.cla and rv93par.cla, for example, are classification
maps produced from the datasets subr9305.img and
r+ndvi93.img respectively by using PAR classification
algorithm and training data 9305-1.roi. Also, the ISODATA
classification algorithm was used to process the datasets
subr9305.img and r+ndvi93.img, which produced classification
maps r93isd.cla and rv93isd.cla.
The error matrices of the classification maps were analyzed by
using the training data 9305-2.roi. The overall accuracy and
K,, statistics were computed for each classification maps.
The results were listed in Table 3, which showed the
Maximum Likelihood is obviously the best method while the
two datasets were not too much different. Therefore, the
Maximum Likelihood algorithm and the two datasets were
used to perform classification for the Landsat TM data of all
four dates in the study area.
4.6 Classification Maps
Training datasets 8505-1.roi and 8505-2.roi; 8705-1.roi and
8705-2.roi; and 9004-1.roi and 9004-2.roi were collected from
false color composite images r8Sfcc.img, r87fcc.img and
r90fcc.img respectively. The Maximum Likelihood algorithm
and the datasets 8505-1.roi, 8705-1.roi and 9004-1.roi were
used to produce classification maps: r85mal.cla and
rv85mal.cla; r87mal.cla and rv87mal.cla; and r90mal.cla and
rv90mal.cla, while the datasets 8505-2.roi, 8705-2.roi and
9004-2.roi were used to evaluate the accuracy of classification
maps. Table 4 presents the overall accuracy and K, | statistics
computed for all classification maps derived from Landsat TM
data of May 14 of 1985, May 20 of 1987, April 26 of 1990 and
May 20 of 1993.
Table 3. Accuracy Comparison of Classification Maps
Method Overall accuracy | Kei
All TM 7 band data without NDVI
MAD 89.86% 87.26%
MAL 92.88% 90.91%
MID 81.71% 77.32%
PAR 85.20% 80.83%
ISD 64.33% 57.33%
All TM 7 band data and NDVI
MAD 90.15% 87.60%
MAL 93.28% 91.40%
MID 85.04% 81.17%
PAR 84.94% 80.52%
ISD 78.79% 72.72%
Table 4. Accuracy of Classification Maps Derived from
Landsat TM data by MAL Method
Date Overall accuracy K.
All TM 7 band data without NDVI
May 20, 1993 92.88% 90.91%
April 26, 1990 86.03% 83.02%
May 20, 1987 92.20% 90.45%
May 14, 1985 91.39% 89.42%
All TM 7 band data and NDVI
May 20, 1993 93.28% 91.40%
April 26, 1990 85.77% 82.72%
May 20, 1987 92.70% 91.06%
May 14, 1985 92.06% 90.24%
4.7 Land Cover Change Detection
Based on the accuracy assessment of classification maps, the
classification maps rv93mal.cla, r90mal.cla, rv87mal.cla and
rv85mal.cla with higher accuracy were used to detect the
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 403