Hi Ben,
Yes, I'm using esri shape file, this is a requirement.
However, if I access the same files with qgis, I see null values, do you
know why?
On 23 Oct 2017 23:38, "Ben Caradoc-Davies" <b...@transient.nz> wrote:
> Matteo,
>
> what is the source of your data? ESRI software and the older DBF format
> often used in shapefiles do not natively support nulls because all fields
> are stored as strings:
> http://support.esri.com/en/technical-article/000005811
> https://en.wikipedia.org/wiki/Shapefile#Data_storage
> https://gis.stackexchange.com/questions/28411/how-to-have-a-
> nullable-field-included-in-a-shapefile-using-the-geotools-library
>
> When reading a DBF file, GeoTools will treat numeric fields that are empty
> or all whitespace or start with '*' as null, and character fields that
> start with a null terminator byte ('\0') as null. You can see the logic
> here:
> https://github.com/geotools/geotools/blob/master/modules/plu
> gin/shapefile/src/main/java/org/geotools/data/shapefile/
> dbf/DbaseFileReader.java#L452
>
> Can you use a format like geopackage that has native support for nulls?
>
> Kind regards,
> Ben.
>
> On 24/10/17 01:05, Matteo Cusmai wrote:
>
>> Hi all,
>> I need to read some shapefiles where some field are nillable and so they
>> could have null value.
>> The problem is that, I don't know why, the features has empty string where
>> should be null.
>>
>> Does someone have the some problem?
>>
>> Regards,
>>
>> Matteo Cusmai
>>
>>
>>
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> --
> Ben Caradoc-Davies <b...@transient.nz>
> Director
> Transient Software Limited <http://transient.nz/>
> New Zealand
>
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