Census 1991 - Output Area Centroids

This dataset shows the 1991 Census Output Areas (OAs) Household Weighted Centroids. An individual Output Area generally covers a sufficiently small area (subject to meeting minimum population / household counts) so that user defined or ad-hoc areas can be created while maintaining a sufficient level of quality. National Records of Scotland (NRS) produces only one set of OAs and creates all other output geographies using the OA as the building brick. Each OA is assigned to an area in a higher geography by first selecting one of the postcodes in the OA as a ‘master’ postcode. The OA inherits all of the characteristics of the master postcode including its assignments to higher areas and its grid reference. The master postcode was selected using an algorithm which calculates the postcode centroid within an OA which has grid references closest to the household-weighted centre of the OA. Revisions and Corrections Correction to 1991 Output Area Household Weighted Centroids An anomaly was discovered when converting the Ordnance Survey Tile Reference to easting and northing where for some records, the centroid for the Output Area was not falling within the boundary of the Output Area.