[Qgis-user] Line dissolve

[Nicolas Cadieux]

Hi,

Thanks for the info.  There was also a line_merge (or merge line) plugin.   The problem with the function that you are indicating is that it take a single Multilinestring and create a simple linestring if the ends are connected.  What I am looking for is a way to select a file made of simple linestrings and to merged them into a single multilinestring if they share a node or share and object that shares a node.  So, for example, if you had two cities separated by a river (and there was no way to cross the river), all the roads would be merged in two objects, one for each city.

This post explains what I would like.  It offer a QGIS 2 script that could help. https://gis.stackexchange.com/questions/198317/join-merge-lines-that-touch-and-intersect-in-qgis

I will share a file with and example of what I am looking for.

Nicolas Cadieux
https://gitlab.com/njacadieux

> Le 29 août 2021 à 17:12, Andrea Giudiceandrea <andreaerdna at libero.it> a écrit :
> 
> 
>> 
>> Nicolas Cadieux Sun, 29 Aug 2021 08:18:08 -0700
> 
>> I did see a merge function but did not find the line_merge plugin in  the repository.
> 
> Hi Nicolas,
> "line_merge" is not a plugin. It is a function  available in QGIS expression / field calculator:
> 
> 14.3.13.53. line_merge
> Returns a LineString or MultiLineString geometry, where any connected LineStrings from the input geometry have been merged into a single linestring. This function will return NULL if passed a geometry which is not a LineString/MultiLineString.
> https://docs.qgis.org/3.16/en/docs/user_manual/working_with_vector/functions_list.html#line-merge
> 
> Regards.
> 
> Andrea Giudiceandrea
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20210830/dd40636f/attachment.html>