[Qgis-developer] Re: How to Set Symbol to Vector Layer that value is NULL

[KSJ]

Martin Dobias wrote
> 
> On Sat, Apr 14, 2012 at 7:39 AM, KSJ <ksj74208@> wrote:
>> Hi All:
>>    I use QgsGraduatedSymbolRendererV2 to simulate colorbar (like
>> matplotlib.colorbar)
>>    use rendererV2.setClassAttribute to show using certain field
>>    But there are some feature where its value of that field is NULL
>>    I found that value NULL seems to be shown as value zero (range 0 - 0 )
>>    Could I distinguish value NULL & zeros with different symbol?
>>    or Could I make a symbol for NULL value?
> 
> Hi
> 
> right now the graduated symbol renderer does not distinguish between
> NULL and zeros. Please feel free to file a feature request.
> 
> Martin
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> 

Thanks Martin.

    my observed data ( some station ) has value zero at a time, and has NO
value ( NULL ) at another time.
    I create a timebar slider to show value of a station on certain time.
    If that station has no value at that time, it show NULL symbol, not ZERO
symbol.
    
    So... maybe I can remove NULL value feature.
    Or I can make some change to the attribute table which has NaN (NULL).
    maybe get dataset's data range, then fill NULL with certain value that
excluded this range
    then give value a symbol to identify NULL, and set RangeListItem's label
to represent

    Thanks Martin again :)

     KSJ

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