Bug report #20809

Merge connected lines and Line orentation dependant position error

Added by Phillip Shelton over 1 year ago.

Status:Open
Priority:Normal
Assignee:-
Category:Labelling
Affected QGIS version:3.4.2 Regression?:No
Operating System:Windows 10 Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:28628

Description

Hi,

I model road traffic and I have found the Line orientation dependant position under Placement under labels, to be a very useful feature.
It allows me to present the direcitonal traffic volumes on the same side of the line object as they occur on the roads I am modelling.

I am also a fan of the Merge connected lines to avoid duplicate labels as it reduces the number of labels and can reduce "clutter" when producing maps.

However, when used together, they sometimes get it wrong. The Merge connected lines to avoid duplicate labels can cause the line orientation dependant position to get it wrong.

I am using a spatialite layer. it also happens for the mapinfo export of the same layer. It seems to get the same links wrong every time for a given QGIS version but possably a different link in different versions (V3.0.0, V3.2.3, V3.4.1 and V3.5.0)

The attribute I have used for the figures is ass_volume, but it happens for any of the attributes. Different attributes seem to have different chances of getting it wrong.

Thank you for looking into this.

Flinders2.7z - spatialite data base with test data (290 KB) Phillip Shelton, 2018-12-14 06:16 AM

lineorientationdependantposition.PNG - figure showing what I want to happen. (51.7 KB) Phillip Shelton, 2018-12-14 06:26 AM

Mergedtoreduceduplicates.PNG - figure showing what happens when I try both options on. (53 KB) Phillip Shelton, 2018-12-14 06:27 AM

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