“Variedades de español”
During much of its history, and especially during the Francoist dictatorship (1939–1975), the Catalan language was ridiculed as a mere dialect of Spanish.[60][61] This view, based on political and ideological considerations, has no linguistic validity.[60][61]
nota: el mapa sola muestra las variedades de
españolcastellano, no las demás lenguas habladas en España
This statement seems to be wrong, as there are at least three languages that are not dialects of Castellano here (likely more)
Afaik, castellano is spoken everywhere, at least as a secondary language. Hence I understand the map to show regional variants of castellano spoken either exclusively or secundary to another local language.
Edit: precised my input a bit since it led to misunderstandandings
