The parallels between Scotland and Catalunya are various - but the key difference is the gamble that England took in facilitating a binding referendum. That result, as we know, was a clear victory for those wishing to maintain the Union with 55% to 45% of the vote. Spain (that is Castile, Valencia and Grenada) in denying a referendum to Catalunya it could potentially have won with 53% to 47% if yesterday's election result can be extrapolated has just stepped into a world of pain.
Catalunyan separatists will now use that minority 47% of votes (on a 76% turnout), which has given them 72 seats in the regional parliament, sufficient to start secession. Spain will not permit it. Everything from the arrest of the separatist leaders to the military occupation of Catalunya is then possible, and Spain will be backed by the capi of the EU.
As much in favour of both self-determination and localism as I am, I cannot say I support the separatists in their proposed actions. They simply don't enjoy the necessary clear democratic mandate for their intentions. Which is also why Sturgeon is farting into the wind with her bluster on Scotland.
The alternative for Spain, to refrain from using force and to allow Catalunya to secede only to watch it collapse without the Euro and without membership of the EU, is attractive in offering an object lesson to Scotland but little else. Effective diplomacy is simply beyond the idiot clowns from Brussels. So we have a recipe for even more chaos in the Med.