@pwessel, WTF do we have to do to calculate a frame in projections like this one where the frame is not along a constant longitude?
julia> cl = coastlinesproj(proj="+proj=ob_tran +o_proj=moll +o_lon_p=40 +o_lat_p=50 +lon_0=60");
julia> grid = graticules(cl);
julia> imshow(grid, plot=(data=cl,), lc=:darkgray)
