[Qgis-user] Joining polylines with overlapping points to 1 polyline with merged points

[Martin Bain]

Hi Jens,
I guess there is more than one way to combine your lines into a single object – you could end up with a multipart object (multilinestring) or a single polyline.

Have you tried the Dissolve command?  I quick test for me produced a single polyline with no duplicate points from two separate lines.
Cheers,
Martin.

From: Qgis-user [mailto:qgis-user-bounces at lists.osgeo.org] On Behalf Of Jens Verwaerde | Natuurpunt CVN
Sent: Tuesday, 13 June 2017 11:49 PM
To: qgis-user at lists.osgeo.org
Subject: [Qgis-user] Joining polylines with overlapping points to 1 polyline with merged points

I have a walking route, that I've digitized in 18 polylines, of which the endpoint is the exact same location as the beginning point of the next polyline.

When I merge these 18 polylines, the overlapping points stay, unfortunately, overlapping points. Visually there's no problem: they behave as 1 polyline, but ... this causes all sorts of problems:
-- exporting to gpx gives faulty routes
-- combining these polylines to a polygon gives polygon rubbish
-- double (or even more) points stay, although I want them to be joined to one point
-- tracing always stops when I reach the end or beginning of a polyline part

How can this be solved?

The only thing that actually worked for me is to make a new layer/shapefile ("traced.shp") and then manually trace the polylines (using the autotrace). In Mapinfo this operation is way much more efficient.


So I'm looking for a way to make 1 polyline with non-overlapping points out of a series of polylines in Qgis.



Jens Verwaerde


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Website: http://cvn.natuurpunt.be



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