Thematic maps (Alphan et al., 2009) are then built based on
separately classified multi-temporal imagery, and comparison
between the classified images can be implemented in terms of
per-pixel basis. This technique can provide detailed “from – to”
information for each class in the process of urbanization
(Jensen, 2004). Since we only would like to examine urban
expansion patterns, the classified classes are merged into the
following two main categories before applying the change
detection technique: the urban area and the non-urban area,
which can avoid the influences of misclassification or
classification errors. Urban expansion then can be analysed
based on bi-temporal and multi-temporal change detection
maps.