Pixellated stroke on paths in Photoshop

[soggymuse]

Thanks for the tips, Meshon. I'll try the shape burst thing and see if makes a difference.

I've asked the requester a couple of times what size he wanted this map to be, but he wasn't very specific so I've upped the size to A4 width (21x21 cm). I've switched to Paint Tool SAI, though (I'm on a short deadline and can't guarantee I'll be able to work over Christmas, so I need to get it finished as fast as possible, and there's no telling how long it will take to fix this Photoshop issue). Unfortunately, 21cm at 300ppi is the largest SAI can handle on my PC so I'll just have to hope it's big enough for purpose... The beauty is that it's vector so it should upsize more easily than Photoshop would.

I still obviously want to fix this issue, so if anyone's got any more advice I'd be very grateful. It's actually going much better in SAI than I thought, though. Someone suggested using vector software earlier and I dismissed it because I only have SAI and it's not the best programme for getting straight lines. However, I've been able to redraw the map in a single morning in SAI that took days in Photoshop, and it's much easier to edit so that off-sets any problems I might have with drawing circles and straight lines in it. (Of course, it helps that I had the original Photoshop version to trace... ¬_¬)

ETA: I've tried the shape burst option Meshon showed me and sadly it's still just as jagged at 100% zoom.