Hi,
Try using 'r.thin' and then 'r.line' wich convert linear raster features to vector line.
Maybe you used r.poly wich try to generate closed poligons, and thats why vector lines are boundaries of your raster contours line, probably.
I used this procedure in past and assure you that worked fine.
I am trying to make some raster maps from contour maps that where
scanned to gif. The inicial maps are in RBG for and I split the channels
in to CYMB so that in the end I have a grey scale map where the contour
(that initial where in brown) are much more obvious, then I run a edge
detection algorithm and the result is fine.
The i pass the image to GRASS and run r.thin and v.poly the problem is
that the final result like a a group of cells all connected (it looks a
bit like thysson poligons). Since I had a bad experience with this
procedure I decided to digitalize the maps with the mouse, this is very
borring and time consumig
Does anyone has a suggestion, or why the r.thin>v.poly>v.digit that is
normally explained in the tutorials work so bad ???
I have send this same email some days ago I haven't seen it in the
mailing list, probably i send it to the wrong email address--
Jorge Samuel Mendes de Jesus <jesus@bgumail.bgu.ac.il>