Catalan Independence Vote October 1: Why? What's At Stake? What Do The Polls Suggest?

Authored by Mike Shedlock via MishTalk.com,
Unless the central government in Madrid forcibly stops elections, the Catalan Independence Vote will take place on October 1.
Politico covers What Spain has to Lose from Catalan Independence.
Catalonia Percent of Spain
Voting Intentions
Poll Source in Spanish: Centre d’Estudis d’Opinió (CEO) June 2017
2015 Advisory Voting Map
Why?