Line tracing

[Ted Cox]

You might try LTPlus - It is a great PD software package. 
Source in on the moon.
Dan Haskell (Flat Earth Systems) in Portland Oregon ported it
to Linux & was charging $100 for it a while back. My experience with it 
is very good.  
Commercial version of LTPlus is called LT4x and is around 3,000 $.
Sorry, I don't have Dan's email any more. 

DORICE at polito.it (Piero Boccardo - Italy) wrote:
>Dear Grass users,
>I'm looking some softwares to vectorise raster map (line followers).
>Do you have any idea where I can find them? Any HW platform could be considere
d.Thank you
>Piero Boccardo