You can do it with GMT.jl. Unfortunately I forgot to port the contour module to the v0.5 version, but it’s now in master. With it you can do (contour the Matlab peaks function, also in GMT.jl)
x,y,z=GMT.peaks();
contour([x[:] y[:] z[:]], cont=1, annot=2, frame="a", fmt="png", show=1)
Without the master version you will have to use the Monolithic method
gmt("pscontour -C1 -A2 -Ba -JX10c -W1p -R-3/3/-3/3 -P > cont.ps", [x[:] y[:] z[:]])
gmt("psconvert cont.ps -A -Tj -Fcont"); # Convert from PostScript to jpeg
