WHAT is the price of liberty? Independence has a cost, as Catalans may appreciate following an election on November 25th that is seen as an unofficial vote on whether the region should separate from Spain.

One way to understand what is at stake is to consider what an independent Catalonia would mean in terms of its trade with its neighbors. Here, Pankaj Ghemawat, a business thinker at IESE Business School in Barcelona, has cleverly weighed in. He has produced proportional maps of the world, showing Catalonia's "exports" to other regions inside Spain, as if they were autonomous too, and to elsehwhere in Europe (see chart below).

Catalans are rightly proud that more than half of their trade flows outside of Spanish borders. France is the top destination, accounting for 10% of Catalonia's exports. But the next three biggest destinations are the regions of Andalucia, Aragon and Valencia. Indeed, if Catalonia were independent, Spain would be its largest trading partner, accounting for more than one-third of its trade. This suggests that, from an economic standpoint, there is much to gain from staying within the larger political entity.

More of Mr Ghemawat's maps are available at his website. For readers ambivalent about proportional maps as a way to present data, read our write-up on the pros and cons on our Graphic detail blog.