A general problem for me with digitized material is that it can be too precise. Sometimes I just need to show a line or surface without sharp borders. I don't regularly need to visualize the exact extent of, say, a wetland to meter or dm level, only show that it exists in approximately that area.
Now I have lines (that I also have buffered 50 m) which I need to "smooth" at the edges. I want the center of the line/buffer to be strong in color. Further away from the center it should be more transparent, and eventually fade away.
How can I accomplish this?