Like everyone involved in Irish genealogy and local history, I spend a lot of time looking at Griffith's Valuation onaskaboutireland.ie. Griffith's is the only Ireland-wide census substitute for the mid-19th century and the site is wonderful, not least because it is free.
One feature, though, has caused much grief to users over the years, the mismatch between the printed records and the maps that accompany them. The maps first used on the site date from several decades after the publication of the valuation, and so can differ puzzlingly from the printed original.
The reason is that Griffith's was a property tax survey. For a century and a half the Valuation Office had to record changes in occupier, holding size, lessor – anything that could affect the value of a holding and thus the tax to be paid on it. Handwritten, copybook-style versions of the original were used to list the changes, which were then handmarked on the office's own copies of the six-inch Ordnance Survey maps.
The maps used by askaboutireland consisted of one full baseline set of these map revisions, undated, but probably from the 1870s or 1880s.
Several months back, askaboutireland, now supported by the Department of the Environment, responded to the problems with these undated maps – by adding mountains of more undated maps.
Every single working revision map from the office now appears to be there, layered one over the other, with up to eight separate maps for some areas, and no way of telling which follows which.
For the moment.
When the full handwritten revision books eventually become available online, it will be possible to date the maps by comparing them with the written records.
The result will be a superb, visual, decade-by-decade archive, showing in minute detail the process of change in every street and field on the island over almost 150 years.
In the meantime, be reassured: it’s not just you. Everyone is floundering.
