Data are available as shapefiles in 100x100km tiles. The location of the tiles can be determined by the key provided with the data. The shapefiles comprise of .shp, .shx and .dbf files.shp - shape format; the feature geometry itselfshx - shape index format; a positional index of the feature geometry to allow seeking forwards and backwards quicklydbf - attribute format; columnar attributes for each shape, in dBase IV formatAlso provided are prj, sbn, sbx and xml files.prj - projection format; the coordinate system and projection information, a plain text file describing the projectionsbn and sbx - a spatial index of the featuresxml - location and other associated informationFree software can be used to open shapefiles, such as Quantum GIS (QGIS) or User-friendly Desktop Internet GIS (uDig) - see links.The classifications found in the attribute table (dbf files) of the shapefiles can be identified using this building class reference sheet (see links). There are 9 Age categories and 19 Type categories. Not all the Age/Type combinations are used, for example there are no Early and Middle Victorian very tall flats (point blocks) in the current edition of the classification (Version 6 September 2012). The current database for the UK does not contain Age categories 1 and 2 and only one type for Age 8. Also the type categories of Medium Height flats 5-6 storeys (3), Tall Terraces 3-4 storeys (5) and Very Large Detached Houses, Sometimes converted to flats (15) have been removed. These are all indicated by the DNU label in the classification sheet. More information can be found on in the The GeoInformation Group guide to the building class dataset (see links).