Thanks for thinking along, but a set of straight lines will give too sharp angles, and if I then have to paint those rounded areas at every corner, it will be a mess. Then it's lots easier to make a topdown render, and draw a Photoshop mask. I still think warping by some straight greyscale area would work, somehow, but you're right, Chris, that's what we really need. Or an easy way to connect two locations by a painted line in the painted shader, like I described.
@Jon; I've just sent some mails to guys who should know if these roads (in the Netherlands) were also straight. I know they have a very mathematical way of making city/town roads, but along te Rhine? The point along this border was to keep an eye on the river, and report/counter any invaders from the north, so the road should be close to it, I'd say, only cutting off little areas of bog. Which I've just inserted, btw; small creek and bridge.
