Hi Using contour(), one can plot pretty pictures (of potential flow); my problem is removing the cutline. If I do: x <- seq(from=-4,to=4,len=100) z <- outer(x,1i*x,"+") contour(x,x,Im(log(z))) everything is fine except the discontinuity along the negative real axis, which derives from log()'s cutline. Before I try to reinvent the wheel, does anyone have a nice way of getting rid of the ugly bunch of contours that correspond to the discontinuity along the cut line? Also, something like contour(x,x,Im((1+2i)*log(z^2/(z-2-1i)/(z-2+1i))),nlevel=33) has a more complicated cut line. Has anyone got any ideas how to improve the plot (ie allow the flow lines to be nicely continuous everywhere except the sources)? -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743