[GRASS-user] snap point to line/break line at given points

[Moritz Lennert]

On 18/04/11 08:19, Johannes Radinger wrote:
>
> Am 16.04.2011 um 17:25 schrieb Daniel Victoria:
>
>> Not sure how to split and label the rivers but to snap the point to
>> the closest river you could use v.distance
>
> I also thought about v.distance. There I get the coordinates of the
> closest points on the new line (stdout). I just have to create a new
> pointfile from the standard output coordinates...or is there any
> simpler way?
 >
> And I also still don't know how to split the lines at these points.
> I thought about v.split but here are segemnts created at equidistant
> breakpoints and one can only set the distance in metres but
> it is not possible to use coordinates as input...anyone knows how
> to do that?

v.edit tool=break coords=CoordinatesOfYourPoints

v.net option=connect + some cleaning afterwards might be another 
possible solution. For each point, it will create a line connecting it 
to the river, breaking the river at the intersection.

v.distance should be able to do the labelling for you.

Moritz

>
> cheers
> /johannes
>
>>
>> Cheers
>> daniel
>>
>> http://grass.fbk.eu/grass65/manuals/html65_user/v.distance.html
>>
>> On Thu, Apr 14, 2011 at 6:36 AM, Johannes Radinger <JRadinger at gmx.at>
>> wrote:
>>> Hello,
>>>
>>> I have a line-vector (river) and some points on that line. First I am
>>> straightening that line with v.generalize (method: boyle). Now, there
>>> is the problem that the points are not exactly on the line anymore.
>>> So I want to snap (move) the points to the new generalized line
>>> again. Which tool is able to do that?
>>>
>>> After that I want to split the line at these points and want to give
>>> the attribute value to the newly created segments. These segment
>>> values should represent the number/value of the upstream point (which
>>> was used to split). How can this be done in GRASS?





>>>
>>> Do you have any ideas to solve these two problems/challenges?
>>>
>>> thank you
>>>
>>> /johannes
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