This paper points out that the records of "block level spatial reference data" don't reflect the centroid of plural polygons for unique address. To improve accuracy of block's centroid, we suggest to recalculate centroid of block using "Digital Map 2500". This method involves dissolving polygons that have identical address using ArcView8.1. Generated multipart polygon improved accuracy by an average of 30m for non-unique, 5.6m for unique records. Importance of data maintenance is also discussed.
