[GRASS-user] LRS and v.build.polylines

[Micha Silver]

I could use some guidance with linear referencing and v.build.polylines. 
I want to get the distances between posts along a bike trail. I have 
vector maps of the trails and the posts. I've added in the start_mp and 
other necessary columns to the posts database. Then I populated the 
start_mp column with values in the order the post points appear along 
the trail.  And I've successfully run v.lrs.create on *some* of the 
trails/posts. But certain trails give this error:

 WARNING: Not enough points (0) attached to the line (cat 1), line skip.

and the distances come out obviously wrong (as if there are gaps) .


Thinking the problem was with extra nodes along the trails, I tried to 
run v.build.polylines but what I get out is a vector with no attribute 
columns (no dbf file attached).

And if I do v.digit on the new polyline vector, I can still see extra 
nodes (in green) along the trail. I must be missing something simple.


So:

How do I properly add a dbf attribute table and columns to the new 
polyline vector? and

What do I need to do to get a clean polyline with no nodes other than 
the actual end points?



Thanks,

Micha