[GRASS-user] v.dissolve for lines?

[Micha Silver]

On 11/05/2010 09:59 PM, Bryan Keith wrote:
>> On 10/19/2010 11:17 PM, Bryan Keith wrote:
>>      
>>> Hello,
>>>
>>> I have a vector line file that has lots of two-vertex lines.  Many of
>>> these two-vertex lines share endpoints and really just make parts of one
>>> longer line.  I'd like to dissolve these lines into one line when they
>>> have the same end point.  It looks like v.dissolve only works for areas.
>>> Is there somewhere else I should be looking?  Thank you.
>>>
>>>
>>>        
>> Did you have a look at v.build.polylines ?
>> Additional note: line vectors have a direction. Two line segments with
>> an equivalent node (end point) will *not* connect if they are in
>> opposite directions. In this case you can try the v.edit tool=flip
>> option (on those segments only)
>>      
> Thank you for the response.  I finally got around to looking at this
> today.  I made a simple example and tested with v.build.polylines, and it
> works great.  Thank you.
>
> However, it turns out that I have many duplicate lines in my dataset.  I
> created a simple example where there are duplicate lines, and
> v.build.polylines doesn't work in that case.  What do I need to look at to
> get rid of duplicate lines?
>
>    

v.clean tool=rmdupl
Might do it if the lines exactly overlap.

> Bryan
>
>