Figure 4. Typified buildings using dendrogram. 
Displacement is first done by computing the 
perpendicular distance to nearest road from building 
with point geometry and the orientation using these two 
points if the building is very close to the nearest road 
regarding symbology and minimum building-to-road 
distance threshold (10 m — 1:50K). In case of polygon 
geometry, nearest vertex of polygon is used and no 
rotation is applied (Figure 5). Namely, geometrically 
unimportant buildings (square shapes) are rotated 
because they are usually derived from a few buildings. If 
buildings are still very close to roads (e.g. buildings at 
the corner of blocks) second displacement is done. We 
can also displace buildings at the same cluster together 
with the one in highest conflict to preserve relative 
locations. Besides, we have to displace the buildings in 
conflict with each other. In this case their intersecting 
buffers can be used and they can be displaced 
perpendicular to intersection points with semi-distance 
of conflict. If buildings have a few conflicts with 
neighbouring buildings, combined displacement vectors 
need to be calculated. This strategy is still in 
development phase. 
  
  
  
Figure 5. Displacement from roads after first iteration. 
4. CONCLUSIONS AND FUTURE WORKS 
In this paper, we present a case study for generalization of 
roads and settlement areas from 1:25K to 1:50K. 
Generalization is a contextual operation and requires object 
and inter-objects level characteristics to be made explicit as 
much as possible. For this purpose, we created blocks among 
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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 
surrounding roads and created voronoi diagrams (polygons) 
within block. Thus, we caught the chance of local analysis 
within the block and local decisions within each voronoi 
polygon to apply generalization operations optimally. 
Besides, object-oriented GIS gave the chance of dynamically 
computing the characteristics of buildings, voronoi polygons 
and blocks. We defined missing rules and the parameters 
experimentally. First results are close to solution after visual 
checking although some editing is required. Next stage of the 
study will be further develop generalization strategy as we 
mentioned above and also evaluation strategy can be 
developed using  characterisations before and after 
generalization. Long transaction mechanism of object- 
oriented database to backtrack in case of bad generalization 
will be considered as well. 
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