I recently had the same issue and was hoping for a response to your question. This morning I found this: http://wiki.inkscape.org/wiki/index.php/Tools#Vectorize.2Ftrace Note the reference to a centerline switch in Autotrace. I haven't tried it myself but it sounds like what we need.
- Robert
On Tue, 4 Dec 2007, Francois du Toit wrote:
I want to trace a map from a bitmap, and using the built in tracing tools I get a reasonable trace. But I was wondering if there isn't a way to trace bitmap lines not as a path shaped as the outline of the bitmap lines, but as a single path going through the center of those bitmap lines. In other words, some kind of line recognition. I tried the edge detection, but that gives you two lines - not really what is required.
Thanks for any help.