A language atlas is a collection of language maps showing the spatial divergence and convergence of languages and/or dialects. The maps in the atlas are usually item- or feature-based, namely each map illustrates the spatial variations of one single linguistic item or feature (phonetic, lexical or syntactic), as represented by the pioneering atlases developed in Europe, Atlas linguistique de la France (ALF, Gilléron and Edmont 1902–1910) and Deutsche Sprachatlas (DSA, Wenker et al. 1926–1956). Also, maps demarcating dialect/language boundaries within a region have b…