The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B3b. Beijing 2008 
(s) 
Figure 3. Proposed system implementation on 
pan-sharpened IKONOS image of Lavasan (Test Area 1) 
Fig.3d is a 8><12 initialization grid on the road binary image 
which are translated in active nodes by spatial C-Means 
clustering in fig. 3e. In fig. 3f these active nodes are connected 
using MST algorithm (Kruskal algorithm) and road centreline 
are obtained which are overlaid on the original image in fig. 3g. 
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Figure 5. Proposed system implementation on 
MS IKONOS image of Lavasan (Test Area 3) 
Fig. 4a shows the second test area that is multi-spectral 
IKONOS image of Lavasan (4m resolution and 115x101 pixels) 
in semi-urban region. Fig. 4 b-g also shows the predefined 
procedures of road extraction. Grey level differences of road 
with its obstacles (for example curbs in this case), leads to 
causing gaps in the road class binary image. 
Kinking effect in fig. 4g is because of densification of grid 
nodes in order to better presentation of the road shape. 
Figure 4. Proposed system implementation on 
MS IKONOS image of Lavasan (Test Area 2)