set polar set rr [-40:10] set rtics 10 unset border unset xtics unset ytics set grid lt 1 lc rgb "blue" f(x) = (x+50)**2 g(x) = sqrt(x)-50 set nonlinear r via f(r) inverse g(r) plot '/tmp/foo.n2p' u ($0>0&&$0<=361 ? $0*pi/180. : 1/0):1 w l lw 2 notit