[GRASS-user] Retyping lines to boundaries

[Roy Sanderson]

Hello

I have a line map that I would like to convert into boundaries, so that
centroids can then be placed within each closed boundary.  However,
v.centroids will not operate on the map, because of course the map only
contains lines, not boundaries.  Is there a way of retyping or recoding
lines to boundaries, so that the centroids can be added?  (GRASS 6.2.1)

Many thanks in advance
Roy