Ordnance Survey of Northern Ireland produced mapping data that is amongst the most detailed and comprehensive in the world and, in 2005, has began to digitize the complete set of historical maps dating back to the 1830s together with the Public Records Office of Northern Ireland.
The vast majority of OSNI's income came from the licensing of its digital mapping data, which, because of the long history of mapping in Ireland (see Ordnance Survey) is amongst the most detailed and comprehensive in the world. Ordnance Survey of Northern Ireland (OSNI) was the official mapping agency of Northern Ireland. In 2005 OSNI began, with the Public Records Office of Northern Ireland (PRONI), to digitise the complete set of historical maps dating back to the 1830s. 
