I wanted to avoid the misleading effects of poorly selected spatial units and inappropriate data categorisation in my next Featured Map. I produced it for a forthcoming CASA Working Paper to inform my analysis of general surname trends in Great Britain by accounting for areas of large numbers of “non-British” names. By running Electoral Roll data through UCL’s Onomap classification I was able to classify people’s names according to their origin, and extract all the names that were not classified as “English”, “Scottish”, “Welsh” and “Cornish”. This method is, of course, not completely perfect but it provides very good context to my analysis. I have opted for 10 categories and small spatial units (Output Areas) to emphasise the clustering of “non-British” names around urban centres. Reproducing the map at Admin. District level gives the impression that the most of Britain is inhabited by people with “non-British” names- something that is clearly not the case.