Feature request #54

label placement

Added by Redmine Admin over 17 years ago. Updated almost 14 years ago.

Assignee:Martin Dobias
Category:Map Canvas
Pull Request or Patch supplied: Resolution:fixed
Easy fix?:No Copied to github as #:10113


A wish: label placement should be improved,
especially for printing, avoiding overlapping and
collisions and repetion of the same label on several
islands of the same feature.

qgis_world_borders_default_labeling.png - QGIS default labeling when collision occurs (225 KB) springmeyer -, 2008-05-02 10:02 AM

mapwindow_world_borders_default_labeling.png - Mapwindow default labeling with collision avoidance on (91.6 KB) springmeyer -, 2008-05-02 10:04 AM


#1 Updated by Gavin Macaulay - about 17 years ago

See also ticket #297 for other label related enhancement requests

#2 Updated by Martin Dobias almost 16 years ago

This really needs more time :-/


#3 Updated by hamish - over 15 years ago


You might look at v.label.sa in GRASS 6.3 for some nice algorithm,

v.label.sa: "Create paint labels, but use a Simulated Annealing algorithm to avoid overlaping labels."

"_v.label.sa_ makes a label-file from a GRASS vector map with labels created from attributes in the attached table. The labels are placed in as optimal place as possible."


good luck,


#4 Updated by springmeyer - over 15 years ago

+ 1 on this being a fairly critical. I would support prioritizing default collision avoidance / filtering as a first feature. This could be a checkbox in the label tab that is on by default and would prevent layers from rendering all their labels when major overlap/collision will occur. This will help basic QGIS aesthetics and performance. An example of the performance hit is that when rendering a world_borders shapefile ( ~500kb) and all the country name labels are placed by default, QGIS hangs unresponsively for about 7 seconds. (I'm running 0.10.0 on Max OS 10.5 with 2GB ram and loading the shapefile from http://thematicmapping.org/downloads/TM_WORLD_BORDERS_SIMPL-0.2.zip).

I just ran a quick comparison with this same sample data in uDIG, Mapwindow, and ArcMap and all three have either a default collision algorithm set or an easy checkbox available to avoid collision and therefore render the world_borders shapefile much faster when labels are requested. This feature will have a big impact on the first-impressions of new users if implemented.

I'll attach two graphics comparing the default labeling in qgis with the default labeling in mapwindow (with collision avoidance).

#6 Updated by Gary Sherman over 15 years ago

This will be addressed with the Google Summer of Code project to enhance labeling in QGIS.

#7 Updated by Stefano Costa - over 15 years ago

Mapserver does the same thing (i.e. automatic removal of labels that collide until there are no collisions). See http://mapserver.gis.umn.edu/docs/reference/mapfile/label (POSITION directive) and http://trac.osgeo.org/mapserver/browser/trunk/mapserver/maplabel.c#L196

This doesn't mean the same code can be used, but it shouldn't be difficult to re-use at least the same algorithm used there.

#8 Updated by Paolo Cavallini about 15 years ago

The bug is a showstopper for milestone 1.0, IMHO

#9 Updated by Maciej Sieczka - about 15 years ago

In #297 there is a somewhat related patch.

#10 Updated by Tim Sutton almost 15 years ago

We will be integrating the PAL label placement library for probably QGIS 1.1. They are finishing some changes and for other reasons we will not be applying this change in QGIS 1.0.



#11 Updated by hamish - over 14 years ago


just to note that the project "Label placement for Quantum GIS" by
Martin Dobias has been accepted for the 2009 Google Summer of Code.

see http://www.osgeo.org/node/895


#12 Updated by Paolo Cavallini about 14 years ago

See also #297; they should be closed together

#13 Updated by Giovanni Manghi almost 14 years ago

  • Resolution set to fixed
  • Status changed from Open to Closed

This should be fixed with the new labelling framework now available in qgis-trunk.

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