[GRASS-user] Selecting Vector Map Segments Within GUI

[Rich Shepard]

   I have two vector maps: one of a stream and its tributaries, the other of
project-specific points on or adjacent to that stream. I want to obtain the
stream length between two points.

   In the GUI I load both layers: streams and proj_pts. I can also load the
attribute table for the streams (it contains only an id number and name),
but cannot select in the map those segments of interest.

   I'm thinking that v.extract would be the way to go.

   What is the most efficient way of calculating the distance between two
points on a stream network? I might have to specify the easting/northing of
each point or create a new map that places those points on the stream lines
themselves

TIA,

Rich