Dang I type slow
You got it ,sometimes easier to trace over the top of it
Like even as stated in the above link It converts it to vector so you can EDIT it.
Most auto trace programs will throw up way too many nodes which you get to thin out.
The trace program will copy both sides of the line with every conceivable flaw creating a node
And when you let the program do it you can loose detail.
On line drawings and plans in my experience its faster to import a picture and trace over it.
I have learned to do this due to the fact that some drawings will cause the computer to lockup from to many god dam nodes.
In short use auto trace to create vector renderings of pictures
Manually trace plans and line drawings.
Best of luck
Dave