[GRASS-user] Splitting lines by other lines that overlap

[Johannes Radinger]

Hi all,

I have two line vectors: LV1) a complete stream network LV2) sections of
the same stream network representing impoundments.

LV2 is a subset of LV1 and fully spatially overlapping. However, the full
stream network consists of polylines with start/end nodes that do not
correspond to the impoundments vector:

LV1 (complete network):
+-------------------+------------------+
LV2 (subset with different start/end nodes)
     +---+               +-------------+

So how can I get the information of impoundments (LV2) into the attribute
table of the first line vector (LV1). A way that came into my mind but
which is somehow cumbersome:

1) Extract the start/end node coordinates each impoundment (LV2) using
v.to.db
2) Use these coordinates in v.edit to break the river network (LV1)
3) Add new categories in layer 2 of LV1 and add an attribute table
4) Use v.distance to query the information from LV2 and copy it to the
corresponding new reaches in LV1
..This is not yet tested and not the most straight forward way.

All this I guess would be easier if there would be something like v.overlay
that works with two line vectors...

Has anybody done similar analysis in GRASS so far?

cheers,
Johannes

tart/end nodes of the
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