Are financial markets "unique" for each "currency pair", or are they simply "translated"?
It's not clear what level of answer you're looking for, so here is a much more basic answer.
There are indeed many exchanges with many different prices. However, if you have noticed that you could make money by exchanging your BTC for USD, exchanging the USD for SEK, and then exchanging the SEK for slightly more BTC than you started with - then someone else probably has noticed that too, and they'll make free money with the manoeuvre just as you will.
As people do this, the prices gradually equalise: you're making BTC more scarce relative to SEK so are driving its price up in SEK (making the last hop less profitable), and you're making BTC more common relative to USD so are driving its price down in USD (making the first hop less profitable).
So it is theoretically possible for such an opportunity for arbitrage to exist. In practice, however, in such a simple case, there are powerful forces acting constantly to equalise the price. As long as it's easy and low-fee to make all three transactions in the chain above (that is, as long as the respective markets are sufficiently liquid), people will make those transactions and the opportunity will naturally disappear.
If you identified a really unobvious opportunity for arbitrage (so unobvious that nobody else saw it before you) and the markets were liquid enough, then you could make a lot of money off it by exactly this manoeuvre!
In fact, very early on, the Bitcoin markets were absolutely full of arbitrage opportunities. The big players were not keen to trade in such risky places (it was routine for an exchange to just close down and run away with large amounts of other people's bitcoin - see the middle point on Forbes's article about this), so there was not such a strong force equalising the prices. As it's become more mainstream, though, more people started taking the free money, and the opportunities have dried up somewhat. So you may very well find that earlier in your dataset, the markets are much more obviously distinct.