Fat and ugly lines in eps export

I have a high resolution map of the world. When I try to export it as an eps with

print('-depsc','-painters', '-loose','test.eps');

the result is something like (this is from a print screen of ghostview)

However, when I zoom in on the matlab figure (same area) this is the result (also print screen)

No matter how small i make the linewidth, the result is always the same. Is there a way to get a nice eps?

Any pointers welcome!