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I have a group of city in a small area with labels. Due to label engine it shows them in a 'random order' (and certainly optimizing) according the space the have.

There is a way, without duplicate the layer, to prioritize just ONE city name to be show whatever the conditions are, the others showed cities order around doesn't matter.

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2 Answers 2

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You can use a conditional expression as you label:

CASE WHEN "MyCitynameColumn" = 'New York' THEN 
    MyCitynameColumn 
END

You can have more than one Case and combine with a Else statement:

Syntax

 CASE
    WHEN condition THEN result
    [ ...n ]
    [ ELSE result ]
 END

[ ] marks optional components

If you have a lot of small areas, resulting in too many cases, your better of using two layers for labeling.

Also you could add a column like Showlabel, fill it with 0 or 1, and use that in the expression

CASE WHEN "ShowLabel" = 1 THEN 
    "Vejnavn"
END

Or you can use an in function in a Case statement:

Case When "MyCitynameColumn" in ('Nibe','New York') then
    "MyCitynameColumn"
End
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  • Thx, but I just want to prioritize a city, not hide the others. we will use different zoom level at the end (9 to 13).
    – Mathieu
    May 11, 2015 at 10:00
  • Thx Jakob but my area is not a small one, it is Europe ;-). So we just need to manage some exeptions (only few). I understand perfectly your way. But in our case is not manageable.
    – Mathieu
    May 11, 2015 at 10:12
  • It is not possibly to databind to the prioritize function. The closest I can think of is to databind a column to both ShowLabel and Always Show label under the rendering tab.
    – Jakob
    May 11, 2015 at 10:14
  • 1
    In previous mapping job I have done, I have used the duplicate layer, that you do not like, for jobs like this :)
    – Jakob
    May 11, 2015 at 10:16
  • We try to create an other style inside the layer and filtering the cities name we want in. We put this in higher layer order. But doesn't work. Maybe can be a trik in the labels function, but this out of our knowledge. So we made a turn around : we have an other layer for capital. So we downgrade those cities in capital order (OSM tag) then this work.
    – Mathieu
    May 11, 2015 at 16:28
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It seems this may be possible in 2.14 and above.

The Priority attribute in Labels > Placement allows you to Edit... an expression for the value. As in the picture below, it seems the Priority variable ranges from 0.0-10.0, and thus whatever expression you come up with should be in that same range.

enter image description here

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