[Qgis-user] Label missing in Weekly

[Bernd Vogelgesang]

mhm,

Nathan, you wrote in the ticket:
"String + NULL = NULL. We don't treat NULL as empty string because it's  
not correct to do so. NULL and empty mean two different things so are  
treated differently."

Sorry, but for "what" is that not correct? This might apply to database  
actions etc. but forcing user to make somersaults with "coalesce" (what  
the f... is that???) to prevent empty labels ... hey! It's just labeling!

Making labeling a nerd-discipline is not fair ;)

Just my 2 cents
Bernd

Am 02.08.2013, 00:02 Uhr, schrieb Nathan Woodrow <madmanwoo at gmail.com>:

> Hey,
>
> QgsExpression doesn't treat NULL and Empty string as the same thing.  
> Which
> is why we don't auto convert.  To convert nulls in a field you should use
> the coalesce("Areatype",'')
>
> See http://hub.qgis.org/issues/8369
>
> - Nathan
>
>
> On Fri, Aug 2, 2013 at 7:35 AM, Larry Shaffer  
> <larrys at dakotacarto.com>wrote:
>
>> Hi Lene,
>>
>> On Thu, Aug 1, 2013 at 2:25 PM, Lene Fischer <lfi at life.ku.dk> wrote:
>>
>>> Hi Goyo
>>> The geometries is OK.
>>> I have a combined label Ex.
>>> Areatype || '\n' ||  $Area   || ' m2'
>>> Now I found that if one field is empty (Even if there is NULL in the
>>> field), then the entire label will not be displayed.
>>>
>>
>> When the expression-based label text was introduced, NULL values
>> supposedly where just converted to empty strings [0], i.e. if Areatype  
>> was
>> NULL, one would expect at least 'm2' to be present in the label.
>>
>> Try enclosing your field name Areatype in double quotes. Also, try  
>> without
>> the $Area function, but still with the || concatenation. If the label  
>> still
>> does not contain any text, then it is probably a bug in how  
>> QgsExpression
>> handles NULL values from the data provider. If so, please create an  
>> issue
>> ticket [1]. Include a test project file, and try to list reproducible
>> steps, if you can.
>>
>> [0]
>> http://osgeo-org.1560.x6.nabble.com/Expression-based-labeling-tp4100735p4100736.html
>> [1] http://hub.qgis.org/projects/quantum-gis/issues
>>
>> Regards,
>>
>> Larry
>>
>>
>>> Regards
>>> Lene
>>>
>>>
>>>
>>> ________________________________________
>>> Fra: Goyo [goyodiaz at gmail.com]
>>> Sendt: 1. august 2013 20:40
>>> Til: Lene Fischer
>>> Cc: qgis-user at lists.osgeo.org
>>> Emne: Re: [Qgis-user] Label missing in Weekly
>>>
>>> 2013/8/1 Lene Fischer <lfi at life.ku.dk>:
>>> > Hello
>>> > I´m using the new labelfunction - it is great!! - but som of the  
>>> labels
>>> are
>>> > missing. I have a small project with only 9 polygons, but only 7  
>>> labels
>>> is
>>> > visible.
>>> > I´ve tried:
>>> >
>>> > Settings to "View all labels in all layers"
>>> > change attributefield and size
>>> >
>>> > Same result. Any suggestions?
>>> > Regards
>>> > Lene Fischer
>>>
>>> You might have invalid geometries. They are not labelled IIRC.
>>>
>>> Goyo
>>>
>>>
>>> _______________________________________________
>>> Qgis-user mailing list
>>> Qgis-user at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>>
>>
>>
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>>


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Bernd Vogelgesang * Siedlerstrasse 2 * 91083 Baiersdorf * +49-9133-825374