Hi Hanlie,
I am getting out of my depth here, and might be leading you astray...
But I had a little challenge a few months ago, wanting to generate
points along a line to then use to create other tangent lines (in
science terms, generating belt-transects across a gully, at randomly
defined distances from start of gully)... sounds vaguely like a simpler
version of what you're doing.
I used a combo of v.segment, v.type_wrapper.sh,... and some beginner
fumbling... from your initial post, I'm guessing you've already got
these under your belt?
If your current hurdle is getting a new column into the table for the
river segments layer, from info in the points layer, could you achieve
this by working directly with the tables (database)? rather than a GRASS
command?? Do you have some linking field between the points and the
segments layers (e.g. segment_cat)? if you do, or can make one, could
you e.g.:
SELECT (start_node_name\ end_node_name) AS segment_name FROM
points_layer_table
and update this to the river segment table??
UPDATE river_segment_table SET new_column_for_label=segment_name
WHERE river_segment_table.segment_cat=points_layer.segment_cat
##note this isn't gramatically correct SQL... just an idea..
Please excuse crude SQL example, I'm still dusting off my old MSACCESS
knowledge and 'converting' it to Postgresql... You can probably get a
select/update process in one easy step with the right SQL sweet-talking?
If i'm off track, apologies for misleading you 
if you get something
out of it, i might promote myself from "complete novice" at sql to
"someone that knows just enough to break things"
Regards,
Shane.
Hi Shane,
Thanks for the suggestion 
I think you're starting where I want to end up, that is, with an
attribute link between the two tables. I want to create this link
based on the spatial arrangement of the lines and the points. So, the
initial 'joining' of points to line needs to be based on their spatial
locations. Then, I need to transfer the right attributes from the
points layer to the line layer.
Regards
Hanlie
2010/12/12, Shane Litherland <litherland-farm@bigpond.com>:
Hi Hanlie,
I am getting out of my depth here, and might be leading you astray...
But I had a little challenge a few months ago, wanting to generate
points along a line to then use to create other tangent lines (in
science terms, generating belt-transects across a gully, at randomly
defined distances from start of gully)... sounds vaguely like a simpler
version of what you're doing.
I used a combo of v.segment, v.type_wrapper.sh,... and some beginner
fumbling... from your initial post, I'm guessing you've already got
these under your belt?
If your current hurdle is getting a new column into the table for the
river segments layer, from info in the points layer, could you achieve
this by working directly with the tables (database)? rather than a GRASS
command?? Do you have some linking field between the points and the
segments layers (e.g. segment_cat)? if you do, or can make one, could
you e.g.:
SELECT (start_node_name\ end_node_name) AS segment_name FROM
points_layer_table
and update this to the river segment table??
UPDATE river_segment_table SET new_column_for_label=segment_name
WHERE river_segment_table.segment_cat=points_layer.segment_cat
##note this isn't gramatically correct SQL... just an idea..
Please excuse crude SQL example, I'm still dusting off my old MSACCESS
knowledge and 'converting' it to Postgresql... You can probably get a
select/update process in one easy step with the right SQL sweet-talking?
If i'm off track, apologies for misleading you if you get something
out of it, i might promote myself from "complete novice" at sql to
"someone that knows just enough to break things"
Regards,
Shane.