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Figure 5: Due to the fact that the topological map of nodes, edges and polygons of the
Administrative Units at the medium scale and the topological map of the generalised
Administrative Units at the same hierarchy level are isomorphic graphs, attributes of Admin-
istrative Borders are transferred from the medium scale to the small scale dataset
Based on the above analysis and the problems in Scenario1, it is consid-
ered preferable to generalise the polygons and then recreate from them the
borders. An issue that needs to be addressed in this case, is that the small
scale borders, which are created by the generalised polygons, do not have
any attributes. The retrieval of the attributes from the medium scale borders
can be succeeded by the use of topology to the initial and the generalised
data. A field is calculated for each border that records the Administrative
Unit codes of the adjacent polygons: that is the polygon on the left side
and the right side of the border. Based the values of this field, medium
 
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